Towns are often built without taking into account environmental factors like landslides, soil erosion, and flooding, which means towns across the globe are going to end up underwater one day.
But sometimes this flooding is deliberate, and innocent towns are caught in the path of the machines of progress and drowned without a second thought.
(Image Via Juan Tello)
For about twenty years this was all that could be seen of a church in Potosi, Venezuela, since the whole town had been flooded to build a hydroelectric dam in 1985.
The rest of the town was destroyed in the process, but the church's brick construction kept it (mostly) alive and intact, and thanks to a drought caused by El Niño the church, and land where the town once stood, was uncovered in 2010.
(Image Via Max Bisschop)
This tower from a church built in the 14th century is all that can be seen of the village Graun in South Tyrol, Italy, a village of 163 homes which was deliberately flooded by the Montecatini company to create Lake Reschen.
Apparently the Montecatini company didn't see any point in preserving a part of Italy's history, but hopefully the colonies of Sea Monkeys that now call this underwater village home will take better care of the place.
You can see many more examples of historic towns that now reside underwater in io9's article These Were Lovely Towns, Until The Waters Came And Covered Them Up