A sign reads “No Trespassing,” though it is evident that few heed the notice.
The Domes were built to facilitate the manufacturing of computers back in the late 1970s to the early 1980s but were never completed, as is evident from a couple of foundations that were started and left to molder. One of the buildings is shaped like a flying saucer, and the other three are as if spheres were joined together, looking like huge concrete caterpillars.
Talk from the locals about the domes concerns ritualistic witchcraft and satanic worship. “Stay out of there and don’t go into the tunnels” is the refrain, and indeed there are tunnels under the eastern end of this facility. But despite all the stories, whether anything more sinister than underage beer-drinking, ghost stories, and the occasional squatter spending the night has ever happened is unknown.
Nonetheless, staying out of the tunnels is probably good advice.
Update January 2018: One dome has collapsed, and the city has ordered the destruction of the domes. They will not stand much longer and have been gated in now as well.
Update November 2019: The domes, despite being ordered for demolition, are still standing. For any potential visitors, please note that the domes are on private property, and being on the property without permission and paying an entry fee will (according to reports by other visitors) result in local law enforcement trespassing you, with the potential for arrest or fine.
Know Before You Go
It's accessible via Casa Grande, Interstate 8 Thorton exit. Then go south one mile and it'll be on the east side of the road.