About 30 miles south of Miami, Florida, in a town called Homestead, lies an unusual—some would say impossible—structure, composed of coral rock. Called the Coral Castle, it has a colorful past. It was the life's work of a reclusive Latvian immigrant named Edward Leedskalnin, who built the complex after being jilted by his sixteen-year-old sweetheart on their wedding day.
source: livescience