Lost World: Schieks Cave (2009)

*Sample chapter from Subterranean Twin Cities*

Lost World: Schieks Cave

Copyright 2009 by Greg Brick

 “Take counsel, cherish not the sun and stars. Come, follow me down into the realm of gloom.” Goethe, Faust

In 1939, Minneapolis Journal photographer David Dornberg went on a “Camera Safari,” as he called it, through a large cave under downtown Minneapolis. He described it as “a ‘lost world,’ weird and spooky—the darkest spot for adventure into which my four years as a Journal cameraman ever led me.” Some may discount this as sensationalistic tripe, but read the testimony of Roger Kehret, a seasoned Minnesota caver with years of experience, in his 1974 booklet, Minnesota Caves of History and Legend: “When cavers think of remote hard to reach caves it brings to mind scenes of high mountains of the Pacific Northwest or the steaming jungles of the Amazon. The most remote and hard to get to cave that I have ever reached is found on Fourth Street near Marquette Avenue in down town Minneapolis, Minnesota.” This chapter describes my own ordeal to reach this lost world.

Schieks Cave, as it has become known among urban explorers, has also been called “Loop Cave,” “Manhole Cave,” or “Farmers & Mechanics Bank Cave.” It got the name from Schieks Palace Royale, a gentlemen’s club that now occupies the Farmers & Mechanics Bank building, under which the cave is located. Journalist Kay Miller once described the nightclub as “topless above, bottomless below” because of the underlying cave, but there’s no humanly enterable physical connection between them.

Schieks Cave is the largest natural cave under downtown Minneapolis, extending for a city block through the St. Peter Sandstone. Carl J. Illstrup, city sewer engineer, who discovered the cave in 1904, described it as a “cave shaped like an inverted bowl,” a description that seems puzzling to anyone who has actually been there. (It’s shaped more like a pancake that has gone awry on the griddle, if that helps.) In 1931, an enthusiastic journalist, Fitzsimmons, waxed poetical about “the beauties of the sewer system” and described Illstrup as “the ruler of this fantastic world.” The discovery of the cave in 1904, during which the crews braved “the lethal breath of deadly gases,” is presented as the highpoint of Illstrup’s life.

The earliest known documentation of Schieks Cave is the 1904 Lund survey, which is good for showing the former “creeks” and “lakes” of the cave. Reportedly, the cave was kept a secret for years because city officials feared the public would think downtown Minneapolis was built on a thin shell that would plunge into a hole in the earth. Another concern was that burglars might have worked undetected and bored directly into the bank’s treasure vaults. By 1921 it was reported that “The entire business portion of the city is built over a series of subterranean lakes and caverns as mysterious and baffling as the Mammoth caves of Kentucky or catacombs of Rome.” The 1929 Lawton survey depicts the cave extensively modified by the construction of piers, walls, and artificial drainage systems. It also shows the 75-foot entrance shaft on Fourth Street and the 15-foot shaft from the cave to the underlying North Minneapolis Tunnel, a sanitary sewer.

In 1952 the Twin Cities Grotto, local chapter of the National Speleological Society, visited Schieks Cave, and it was written up for the Sunday supplements. The late architectural historian David Gebhard, author of many architectural guidebooks, was a member of this club. In 1983, a successor organization, the Minnesota Speleological Survey (MSS), visited the cave, and their lurid account of the gloomy cave whose walls were black with cockroaches, and the roaring sewer that ran under it, only fired my enthusiasm to get there someday—one way or another. Perhaps even by climbing up from the sewers rather than down from the streets?

The earliest published account of someone visiting Schieks Cave without official sanction has been quoted above. In a chapter titled, “The Minnesota Rovers Great Manhole Cave Expedition,” Kehret went on to reveal how the Rovers, an outing club, dressed as sewer workers, surrounded the entrance manhole with barricades, and used a truck-mounted winch to remove the heavy, hexagonal lid (which in recent years has been welded shut). Getting there must have been more than half the fun, however, because Kehret said little about the cave itself, except that it was “almost filled with sand, concrete, pipes and other debris.”

In 1993, John and I examined the storm drains under the Minneapolis loop with the hope of getting into Schieks Cave. Located far below street level, the system drains to the Mississippi River by a large outfall in the milling district. With reference to the most famous sewer of Antiquity, it’s the very “Cloaca Maxima” of Minneapolis. Because no connection from the storm drains to the cave, or to the sanitary sewer known to run under the cave, was found, we shelved the project. Shortly thereafter I left for the University of Connecticut, where I did graduate work on barite mines.

In 1996 a college student, along with several friends, began a series of attempts to get to Schieks Cave. He created a website, perhaps the first of its kind in this area, called “Minneapolis Draining Archive,” where he posted trip reports of these and other adventures. After exploring the storm drains without result, he tried wading upstream in the North Minneapolis Tunnel (NMT). This sanitary sewer, eight feet in diameter, carries the great river of human waste from the Loop, and runs directly under the cave, as noted above.

NMT is the very gut of Minneapolis. Wading upstream is fatiguing owing to the swift, chest-deep current (2.5 feet per second), and the well-lubricated invert (floor). Occasionally one of them would lose his footing, even to the extent of full immersion in the warm, gray fluid, and get swept back to the starting point. He persevered to the extent of going two city blocks, with four blocks remaining to get to the cave. In desperation, he considered driving climbing pitons into the sewer walls, but nothing came of it. While NMT has been called a lot of things over the years, my favorite was the “Silk Road,” an allusion, you might imagine, to all the little bits of toilet tissue swirling through there. It took an effort to maintain a sense of humor in such grim surroundings.

In 1999, National Geographic Adventure magazine commissioned a writer to report on urban exploration, which came to focus on the efforts to get to Schieks Cave. By this time I had met him and we agreed to join forces. I advocated an “upstream strategy”: to find a safe entrance to NMT upstream from the cave and “go with the flow,” rather than buck the current. The summer of 1999 was devoted to this task. In keeping with the magazine’s hip, youthful, target audience, however, my critical role in the exploration, without which it would not have succeeded, was to be downgraded to that of a “wizened elder” who “smokes cheap cigars.” All the locations appearing in the photo shoot, for example, were picked by me, and I was the only person who knew how to access them. But I was in my thirties at the time, a bit too long in the tooth for their demographic. By contrast, the youthful explorer was compared with world-renowned physicist J. Robert Oppenheimer, apparently for things like crafting a make-shift sewer canoe out of “an old file cabinet.”

The first upstream entry point we investigated was the venerable Bassett Creek Tunnel. Running below this storm tunnel for a short distance was a sanitary sewer, the whole thing forming somewhat of a double-decker arrangement. The plan was to drop into the lower tunnel and head downstream to the cave. But upon removing the lids in the floor of the upper tunnel, and allowing the mephitic vapors to exhale, we got cold feet. The sewage just seemed to be moving too fast down there.

More to be feared, however, was the inferred existence of a waterfall at some point along the sewer line. While at Bassett Creek the sanitary sewer was somewhat near street level, at Schieks Cave, NMT is 90 feet down. Somewhere along the way there had to be a big drop. And the small-scale sewer maps that we had didn’t indicate details of this nature.

Tracing the sanitary sewer downstream by peeping through the holes on manhole lids, we found a “good lid” farther along, on a little used side street. The sewage was not moving so fast here, but it appeared deeper. Surrounding the manhole with orange cones, we descended a rope ladder and walked downstream. My thigh waders soon overtopped and filled with sewage, so that I appeared to have elephantiasis. Condoms, distended with raw sewage, dangled from the vaults above our heads. The hypothetical waterfall, located near Déjà Vu Nightclub, proved very real. Affixing a safety line to a pipe jutting from the walls, we approached the slippery brink of the cataract and peered into the abyss. I recalled the ending of Edgar Allan Poe’s Narrative of Arthur Gordon Pym, where a chasm opened to swallow the hapless explorers.

This sanitary waterfall marked the beginning of the deep NMT proper. From here, NMT ran under Schieks Cave and then on towards the treatment plant. We saw ladder rungs in the wall of the dropshaft, in the midst of the waterfall. We briefly toyed with the notion of sealing ourselves in trash bags, diverting the waterfall, and descending the ladder, but it all seemed just a bit too weird. Such situations are dangerous for another reason, namely, that the turbulence of the splattering sewage causes deadly gasses to bubble off. We gave up on that approach.

In August, 1999, we investigated another tributary of NMT, running under the warehouse district. We found good lids situated among deserted construction sites, but here again we faced the daunting prospect of a waterfall. Soon after, the young explorer returned to the manhole with his buddies, descended into the tributary on a rope ladder, and walked several blocks downstream, where he encountered a steep flume rather than a waterfall. Once on the slippery slope they could no longer control their descent, rocketing down the flume in a shower of raw sewage.

At the bottom of the flume, they bobbed up into the waist-deep NMT, 90 feet below street level. One person had lost his flashlight, another his glasses, yet another, both shoes. One of them swallowed sewage, contracted giardiasis, and later had to undergo a course of antibiotics. Bloodied by the harrowing descent, they made their way to Schieks Cave, where they spent 20 minutes.

The young adventurer had invited me to go on this trip, but I pointed out that there was rain in the weather forecast. His answer? They had life jackets. I don’t think he had the faintest clue about the extreme danger of entering tunnels of any kind while it’s raining. Despite every precaution, for example, even professional tunnel workers have been swept to their death, as tragically happened in St. Paul in 2007. It’s not something to be taken lightly.

Awaiting the perfect “beach” weather demanded for deep-earth sewering, John and I were ready to ride the flume down to Schieks Cave a few weeks later. I constructed a new rope ladder with Perlon climbing rope and wooden dowels, making it thirty feet long because that’s the average thickness of the Platteville Limestone in the Twin Cities Basin, and hence the depth of many shafts thereabouts. I designed a new type of rigid ladder that could be floated into position and rapidly assembled. The floating ladder could be hitched to my belt with a rope and towed behind in the stream, leaving my hands free.

The multitudinous supplies in our bulging backpacks were encapsulated in three layers of plastic contractor bags. By the time we got to the manhole we must have looked like walking tool chests. Someone approached us and asked what we were doing, to which we made no response. The equipment drop having taken place flawlessly in a drive-by operation, the rope ladder was unfurled and secured in minutes, the disposable floating ladder was lowered away, and soon both of us were securely at the bottom of the shaft.

But alas! What hadn’t been anticipated was the force of the sewage flow in the narrow confines of the pipe. Perhaps it was the wrong time of day. The damned thing was running half full. I clutched at the slimy walls to avoid getting swept away. The air was tropical. I burst into a sweat. I also felt bad. John had never developed a taste for sanitary work, and I had downplayed this aspect of the voyage to avoid facing the fearful prospect of descending to the cave alone. When you go to Hell, you want to take somebody with you.

There wasn’t much time for debate. The Devil himself seemed to be tugging on the other end of my new ladder, trying to drag me down into the abyss of raw sewage under the city. It was a struggle just to get back out of the manhole, because the rope ladder had sprung up out of reach like a rubber band in the mean time.

We crept from the manhole and lay on the ground like drowned rats, glistening with human waste. The operation had been an embarrassing disaster. Worse, owing to changes at the construction sites with the good lids, the entrance soon thereafter became unusable. Schieks Cave, once within my grasp, had receded to infinity.

An incredible piece of good fortune came our way the following year, however. While walking through the deep storm drains one day in April, 2000—the very ones we had carefully examined years earlier—John heard cascading water in the darkness ahead of us. We discovered that thirty feet of the floor of a storm drain had collapsed into a void in the sandstone, and storm water was pouring through the break. Ducking through, we entered a large void and found a collapsed sanitary sewer. The significance of this struck me instantly. We finally had upstream access to NMT. The road to Schieks Cave was wide open.

This fortuitous window into the abyss, ephemeral as it may seem, was superior to the flume route in that we could walk to Schieks Cave straight from the river, with the ability to visit the cave as often as we liked, at least until the break was repaired. By contrast, the flume ordeal was so horrific that everyone else swore off sewering afterwards (which I think was a genuinely wise decision).

In May, 2000, having regrouped and secured proper gear, John and I made our first trek to Schieks Cave. We followed a well-traveled route into the Minneapolis underworld, which merits closer description.

We climbed down an old manhole into the huge brick outfall chamber along the water front. Although the pea-green water was only knee-deep, we hugged the walls like mice, avoiding the deep drop-off in the center. The water was charged with flotsam, mostly wood, styrofoam, and dead carp, which surged back and forth as if under the influence of tides. Periodically, the surge generated a tidal bore a few inches high that chugged noisily up the tunnel for several blocks.

I recalled my first visit to this chamber years earlier, before I knew about the manhole entrance. Quite alone, I swam up the outfall from the river in a wetsuit, having first filled the wetsuit with “clean” river water, so that I wouldn’t get the nasty, pea-green soup next to my skin. It was a hot summer day, and upon arriving inside, to prevent overheating in my wetsuit, I took a cue from the famous French cave explorer Norbert Casteret, who sometimes explored in the buff. You’d never dream of doing that in our present electronic age, considering how many explorers you might bump into. Nowadays, I hear, it’s all the rage to have someone take your picture at such times, and post it on the Web for all to see.

But I digress. Hiking up the storm drain, we established “base camp” at the Wash-Port regulator, located under Washington and Portland, of course. This was a key place in the Minneapolis underworld because the storm and sanitary systems were separated by little more than a low wall, and you could cross freely between them. A dry, concrete room, well above the water line, was available for storing equipment. In recent years, this connection has been completely reconstructed, severing any access.

Leaving base camp, we passed another well-known subterranean landmark, the Iron Gate, a heavy steel flap door that had to be propped open so that explorers could crawl underneath. The Iron Gate marked the beginning of the really deep stuff. When I heard it bang shut behind me I usually got a heavy feeling, a sense that I was now committed to whatever endeavor was before me. From there we hiked several blocks up the Washington Avenue tunnel and turned up a side tunnel, arriving at the sewer break. There was no chance of getting lost because the street names are marked on little bronze plates for the convenience of sewer workers.

The sewer break was very close to Schieks Cave, yielding access to NMT one half block downstream from the cave. I volunteered to wade up to the cave and affix a yellow polypro safety line for the convenience of the trips to follow. Lowering myself into the raging current of raw sewage, however, I could hardly maintain a footing on the slippery invert. I inched along, advancing sideways, while paying out the safety line behind me. I clutched at every little irregularity in the stone walls, like a rockclimber. The walls of NMT were coated with a vile jelly that I hadn’t seen before. The violet slime of the deep sewers!

Arriving at the shaft to Schieks Cave, I found a crude wooden ladder consisting of a single upright and crosspiece, like a crucifix. I had to laugh. It was the one that the young explorer had brought down the flume. Even though the ladder had been sitting there only nine months, it appeared ancient, showing how corrosive the sewer environment was. Tongue in cheek, we dubbed it the crucifix ladder, commemorating his ordeal.

Both of us had been waiting to see Schieks Cave for so many years that we experienced a sort of “rapture of the deeps” upon our arrival at the cave. Perhaps tiny bubbles of sewer gas had lodged in our brains. We gazed up the 75-foot shaft to the street, the entry point for official tours in the past. It was like looking up from the bottom of a deep well-hole, light streaming through ventilation ports in the hexagonal lid far above us. Lid fragments lie scattered about our feet, lids that had tumbled down the shaft and smashed like cookies when someone got careless.

Although this sandstone cave was extensive, its flat limestone ceiling was rather low, obliging us to go about like apes, balancing on our gloved knuckles as we made our way among the sand dunes with grunts of satisfaction. Large natural sandstone pillars, called “stone islands” on the old real estate plats, formed a maze within the cave. Pyramid-style concrete piers supported the ceiling in many locations. It was another example of the vaguely Egyptian appearance of deep sewer architecture.

A major arm of Schieks Cave ran under the eleven-story Title Insurance Building, which is heavier than the adjoining four-story Farmers & Mechanics Bank. Consequently, there were more of the pyramidal piers here than in all the rest of the cave combined. This part was flooded with a lake of stagnant, bubbling sewage—“the Black Sea”—which years later mysteriously dried up, leaving a polygonal-cracked mudflat, covered with a whitish efflorescence, like a dusting of snow.

Inside Schieks Cave there was a concrete chamber that resembled a baseball dugout. The chamber contained a ceiling spring that was dubbed “Little Minnehaha Falls” by sewer workers long ago, and it was labeled as such on Dornberg’s 1939 map. Groundwater poured from a bedding plane in the limestone ceiling, forming a curtain of water, and deposited vertically striped black and white, or “zebra,” flowstone, on the walls of the room. The black mineral is probably manganese. In fact, the crown jewel of mineral deposits in Schieks Cave, a formation that we dubbed the Black Medusa because of it shape, is made entirely of this mineral.

Using a high-quality mercury thermometer, I took the temperature of Little Minnehaha Falls and found her very feverish. The groundwater temperature was 19°C, more than twice the expected value at this latitude, and warmer even than surface water for that time of year. Upon reporting the results in a professional newsletter, I speculated that this thermal anomaly could be the result of heat generated by human activities in a densely urbanized area. Boiler rooms, for example, warm up the surrounding ground.

The subterranean waterfall was a good place to ponder the old controversy about the origin of Schieks Cave. Everyone agreed that the cave was formed by the mechanical erosion of the soft St. Peter Sandstone by running water, a process known as “piping.” However, one view is “that the cave was formed 10,000 to 15,000 years ago,” and is “a relic of the Ice Age.” The contrasting theory, based on the testimony of sewer engineer Illstrup, is that the cave “may have been formed by water escaping from an abandoned artesian well and washing the sand into the sewer.” The sewer referred to is doubtless the North Minneapolis Tunnel, on which construction began in 1889. My own contribution was the discovery that the “Old Artesian Well,” at least as marked on Dornberg’s map, does not exist. Nor did it ever exist, because even if it had rusted away completely and the hole had become buried with debris, there would still be a corresponding drill hole through the ceiling, which there was not. Little Minnehaha Falls, it seemed to me, or something like it, could have provided the source of water.

Something else was conspicuous by its absence, however. Where were all the cockroaches? I had been sold on that point! Not a single one, not even a dead roach, anywhere. Nor were there any bats or rats, for that matter. Instead, the cave was dominated by a sort of fly-and-worm ecosystem which, as I later learned, has been found in other polluted urban caves around the country. The Schieks Cave biota is basically a guanophile (excrement-loving) community, with earthworms covering the floor like spaghetti near the broken sewer lines. Fungus gardens, fed upon by swarms of fungus gnats, in turn supported the spiders in the cave.

The flood history of Schieks Cave was enough to concern the most intrepid sewer-explorer. One source said, “after heavy rains the sewer backs up leaving water and debris scattered around the cave.” Indeed, we found plastic soda straws and tampon applicators (by far the two most abundant types of detritus) on ledges several feet above the cave floor.

Two weeks later we returned to Schieks Cave to get video footage and continue our exploration. To maintain a coherent narrative in the sandstone maze we filmed the cave in a clockwise direction, following Dornberg’s 1939 “route of camera exploration,” using the survey maps as a basis for commentary. The whole thing went quite well, except for a few expletives, and I showed the resulting video in my geology courses at a local college for years afterwards.

One of our goals during the second trip was to explore what Lund’s 1904 map called the “North Western National Bank Tunnel,” which appeared to run under the floor of Schieks Cave. The notion of exploring an obscure tunnel under an obscure cave appealed to my sense of the utterly remote, and I wanted to take a stroll down there. I finally located the rusted manhole lid in the floor of the cave and banged away until it came loose. Unfortunately, the passage was filled to the brim with a nauseous, yellow-gray liquid. The “bank tunnel” was really a sewer tunnel. The video guy recorded my disgust.

After the first trip to Schieks Cave I was convulsed with a violent illness that I initially attributed to food poisoning. But by then it was becoming apparent that similar episodes had followed by a day or two any visit to the North Minneapolis Tunnel. The symptoms involved rolling about on the bathroom floor while puking my guts out, for hour after hour. I could barely hoist myself onto the pot for the diarrhea part. My cats would stroll through occasionally to use their litter box, and seemed to view me with great pity. One time, worse than the rest, I went down in the cellar for buckets and was disgusted to observe that vomit had dripped through the floorboards. Have you ever been that sick?

Having perceived the pattern, I determined to at least have the honor of giving the sewage sickness a name, “Rinker’s Revenge.” The analogy was with Montezuma’s Revenge, of course. The eponymous Andrew Rinker, Minneapolis city engineer for 36 years, was the Father of the North Minneapolis Tunnel. Entering NMT—or even getting near it—was a prescription for the ailment, at least for me. Never on any occasion that I became sick did I recall having actually swallowed sewage while in the tunnel. I did notice, however, that whenever a beam of light illuminated the tunnel, the air was laced with shining droplets and rainbows. And once, leaning down near the surface of the stream, I got a soapy taste, as if the air I inhaled contained enough droplets to generate taste. I later learned that these infectious droplets are well known to aerobiologists as “coliform aerosols,” and contain fecal bacteria, among other things. The NMT rainbows were not friendly harbingers.

Who could tell what other evil bugs lay in wait for us in the depths of the hexagonal abysses? To stave off the agonies of Rinker’s Revenge on our second trip to Schieks Cave, I devised elaborate precautions worthy of the Andromeda Strain. I wore a full-face respirator with chemical cartridges while walking through NMT. I packed a decon kit consisting of hydrogen peroxide spritz bottle, latex gloves, clean towels, and so forth. I wore a raincoat, neoprene chest waders, rubber gloves and rubber boots.

Wearing a mask in NMT had its downside. While I was protected from the infectious mist, the face piece fogged over and was unbearably hot. But the cartridges were so effective that I didn’t even smell hydrogen sulfide, the Chanel No. 5 of sewer scents, at any time I was down there. Nor did I get sick.

Upon leaving Schieks Cave after our second visit, and descending into the murky NMT, I decided to ride the stream all the way down to the Wash-Port regulator instead of returning via the break in the storm drain. I was curious to see what was down those six blocks of dark tunnel. John, less foolhardy, thought there was too much risk of getting swept away, all the way to the treatment plant, and agreed to meet me back at the regulator, where the two systems crossed paths for the last time.

Entering NMT for the home lap—respirator firmly clamped over my face—I abandoned myself to the powerful current, which swept me along on tiptoes. The consequences of losing my balance or passing out in raw sewage up to my neck were too hideous to contemplate, even with a respirator. Within a short time, John’s light had faded away and I was alone in the world, or rather under it. I could hear a muffled roar ahead of me in the darkness, where the sewage plunged into the regulator. After a while I got used to it, however, and was able to stop myself and explore a few interesting side-passages along the way.

The enormous sewer break that allowed us to portage from the deep storm tunnels to Schieks Cave was soon found and sealed by Public Works, however. The task of mending the break required drilling a special-purpose 4-foot diameter shaft down to the tunnel. The fortuitous connection had existed less than a year, but I had no doubt that new portals would develop in the future, as the mortar decayed.

Apart from the intrinsic interest of Dornberg’s “Lost World,” Schieks Cave was important because it gave us access to a system of voids that ran along the tops of the tunnels under the Loop. Consulting Peele, the mining engineer’s “bible,” I found that these voids, called “overbreaks,” are a by-product of tunnel construction. Located outside the concrete tunnel linings, in the surrounding sandrock, overbreaks are the most remote physical spaces under the city of Minneapolis. The overbreaks ranged in size from tight belly crawls to Gothic cathedral passages 15 feet high, but most of them involved painful hands and knees crawling, for which I evolved a special “marsupial pack” that slung from my belly, to carry basic supplies. My hope was to use this secret system of dry passages to get from Schieks Cave to other caves depicted on the sewer plats, such as the Nicollet Mall cave, mentioned in a 1929 newspaper clipping.

In the end, Schieks Cave itself was thus an advanced base camp for exploring the far-flung archipelago of caves under the Loop. The old nightclub cave, ringed about by deadly sewage waterfalls, became the jumping-off place in the hunt for ice age caves among the cathedral overbreaks.

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