St. Thomas, NV was originally a Mormon settlement, a town of about 500 people. Its last resident left in 1938 as the town started filling up with water as a result of the construction of Hoover Dam. The town remained under Lake Mead until the recent drought which caused the lake to recede.
http://www.nps.gov/lake/historyculture/stthomas.htm
http://www.flickr.com/photos/digitalartform/3448301263/in/gallery-hippie-72157627297288753/
http://www.youtube.com/watch?v=kQTW7Pd1vqc
http://www.flickr.com/photos/digitalartform/4066181663/
http://www.neatorama.com/2012/02/26/techno-viking-action-figure/