I put out a call last week for Missouri and Illinois Urban Legend requests and this was a request from Missy A. This complex was known by several names: Aqua Dome, Echo Dome, and the portmanteau Equadome. Origianally it was St Charles' Water Treatment Plant Number 2, used from 1941-1946 to purify water that had been used to make TNT. So, if you are a long time reader of this blog, you may surmise that Equadome was near the Nuclear Waste Adventure Trail, aka Weldon Spring Site Remedial Action Project (WSSRAP). A lot of teenagers got up to a lot of shenanigans in this area in the 70s and 80s and only learned as adults how hazardous those areas were in terms of toxic waste.
The Equadome was dangerous in other ways, too. I think everyone probably has a tale of some nearby park or cemetery they heard about in high school where satanic rituals took place, and Equadome was one of those places. I don't put a lot of stock in the "devil worship" of the 80s and 90s, as I think it was mostly kids screwing around and trying to be different, but there were reports of animal carcasses, candles, pentagrams, and unidentifiable dark stains.
It was a big complex of buildings, with multiple stories and sub-basements, and at least one person fell to their death there and was impaled on a spike at the bottom of a shaft. There was also an incident where a sniper shot a pastor's wife on Highway 94 from the top of one of the towers, according to a quote from Lieutenant Craig McGuire in the book Weird Missouri. And of course, as the urban legends would have it, many unaccounted for deaths happened there, which were known to regular explorers.
Several sites reference photos taken by Jason Pettus before the complex was demolished in the late 90s. His site is no longer active, but someone did post a lot of his pictures to Underground Ozarks. Beware: if you are into urban exploration, Underground Ozarks is a black hole that will suck away hours of your day.
The demolition of the site in the 90s is also noteworthy, as it was apparently the Rasputin of buildings. Some say it was built to withstand bombs. and apparently it took several rounds of explosives to bring the building down. Retired Army Corps of Engineers engineer Karl Daubel is quoted in Weird Missouri as saying that the first round just moved the buildings over about a foot and set them back down again. We talked to Karl ourselves the last time we were at the WSSRAP museum, where he works as a guide there. For more of the weird and wacky surrounding that area, stop in and see him sometime!