My own introduction to subterranean Nicollet Island involved more travail than treasure, as a member of a roving exploratory herd on a cold, snowy night in the winter of 1989. One guy removed the lid, which was partly in someone’s backyard, and a big cloud of steam billowed out. We scrambled down the shaft into the toasty warmth of the tunnel system, 20 feet below the surface, which carried the island’s water main.
What makes the Nicollet Island tunnel system so uncomfortable is that the passages are only 5 feet high and half as wide, forcing us to go about Quasimodo-style for hundreds of feet while straddling a water main and carrying a big rucksack full of heavy tools. By the end of the trip, just standing upright felt positively delightful. The fetid tunnel air was unwholesome to breathe, stagnant and tainted with raw sewage. For while most of the passages were floored with dry dirt, the water mains occasionally ran through pools of raw sewage. Although the water in water mains is under positive pressure, and should leak outwards, rather than inwards, if there was a hole in the pipe, I still found the situation unsavory to contemplate. Maybe that’s why I drink so much bottled water…
Nicollet Island’s ring tunnel intersected Satan’s Cave, its best known cave. To get into the cave we’d squeeze out through a window in the brick wall of the ring tunnel and lower ourselves a body’s length down to the sandy floor of the cave. In one spot, the ring tunnel passed through the cave itself, and being unsupported below, resembled a brick bridge inside the cave. The cave itself consists of three parallel passages dug out of the sandrock, only two of which are presently interconnected, the third having been isolated by a roof collapse years go. Each passage was a dozen feet high and about as wide, running a hundred feet or so. One guy went over the cave with a metal detector pretty thoroughly and dug up numerous old artifacts, such as bits of old horse tack. These he later reburied in the ground in a sort of time capsule.
Satan’s Cave, of course, contains the famous “chapel” where a half-dozen devil’s heads have been carved into the walls, in bas-relief, near floor level. The devils had open mouths, where you’d place candles to illuminate the room. The flaring nostrils were delicately carved through so that light would beam forth from them also. In the center of the room was an “altar” and “candelabra” with candles. Was it really used for satanic “worship”? I doubt it, but we always brought votive candles with us, lit them, and then lay in the dry, beach-like sand for a catnap, as it was a nice place to relax from the painful contortions required to get there. The back wall of Satan’s Cave was bricked over, but the passage almost certainly once led out to the river.
EXCERPTED FROM SUBTERRANEAN TWIN CITIES.