The Mars Desert Research Station (MDRS), operated by the Mars Society, sits about 15 km northwest of Hanksville on a remote spur road across the San Rafael Swell. It is a functioning simulated Mars habitat: a cylinder of white modules housing a crew of six, equipped with airlocks, geology labs, and a greenhouse. Research crews conduct simulated Mars missions here for weeks at a time, staying in the hab and going outside only in mock spacesuits.
The station is not generally open to casual visitors, but the exterior can be seen from the access road and the Mars Society sometimes organises open days. The surrounding landscape — eroded badlands of red and grey mudstone, completely treeless, eerily flat — is some of the most Mars-like terrain on Earth. Worth the detour even just to stand in it. The road in from Hanksville is unpaved and impassable in wet weather; check conditions before attempting it.