From 1920 to 1940, Edward Leedskalnin built this unusual monument, reportedly after being jilted by a 16-year old love back home in Latvia. Coral Castle is made from 1,100 tons of coral rock that was carved into various shapes, though it is somewhat a mystery exactly how this was possible. Engineers and scientists have been stumped. The Castle walls and gates surround the carvings of furniture, creating a sort of “roofless” castle.