Villa Epecuen, an old town in South Buenos Aires spent nearly 25 years underwater. A holiday destination in the 1920s, it was built on the banks of a salt lake. The town went underwater after a dam burst in 1985 and submerged it in 33 feet of salt water. The residents who waited for the water to recede soon deserted the place. In 2009, the place emerged again as the water receded.
Source: Unbelievable Facts