Potosi

This Venezuelan town was abandoned and then flooded with water in 1985.

Potosí was a Venezuelan town in the western state of Táchira. The town was deliberately flooded by the Venezuelan government in 1985 to build a hydroelectric dam. All that remained of the town, was a cross on the top of the church steeple which was visible above the waterline.

History
Prior to 1985, Potosí was a town of approximately 1,200 inhabitants. The then-president of Venezuela, Carlos Andres Perez, flew in by helicopter and announced that the town was to be evacuated and then flooded to build a hydroelectric dam. The houses and the colonial church were abandoned and most of the residents moved throughout Venezuela. The waters of the Uribante Reservoir, once covering 20 square kilometres, submerged the town with the exception of the 26 m tall church steeple.

Reemergence
In 2008, the cross started to rise higher and higher out of the water, revealing more of the gothic structure below. The water of the reservoir was receding, due to a drought caused by the weather phenomenon called El Niño, revealing what the lake had concealed for more than two decades. By 2010, the water had receded almost entirely. The church, grave markers, the ruins of houses and the outline of the former town square have reemerged with the church entirely exposed, although only its facade remains.

Sources: https://en.wikipedia.org/wiki/Potosi,_Venezuela and http://www.atlasobscura.com/places/drowned-church-potosi