The abandoned Villa Sbertoli in Pistoia, Italy. Once a private residence, it was turned into an asylum by Professor Augustine Sbertoli in then was used as a political prison under the Fascist government, then an asylum again.
Though it is called Stargate, this alien landscape is found on Earth. One of the submerged caves, or blue holes, of the Bahamas, it is extremely difficult to explore but a treasure trove for scientists. Photo by Wes C. Skiles for National Geographic