Arizona Nuclear Missile Bunker for $400k
theguardian.com
theguardian.com
Some people with a lot of money like to have a comfortable bunker. Assuming that it was not used for survivalists purposes, adding a clear dome to let in daylight, and lots of room for workshops, hobby trains, etc. I live in Arizona (central mountains) and I am familiar with the general area around Tucson where I think this is located.
That for posting this - fun link, and I enjoyed the 3D tour.