Came here to add that. I saw it as kind of a joke (and there is a Star Trekky 90's techno-optimism to the whole thing that I miss now) due to the Pauly Shore parody of it, and so I went on a whim when I was in town. It's actually an impressive work of engineering in its way, and used to study ecosystems to this day although it is no longer sealed. I'd recommend a visit to anyone.