Sugarloaf Key Bat Tower

It resembles an Aztec-inspired fire lookout, but this wooden tower is actually one real-estate developer’s vision gone utterly awry. In the 1920s Richter C Perky had the bright idea to transform this area into a vacation resort. There was just one problem: mosquitoes. His solution? Build a 35ft tower and move in a colony of bats (he’d heard they eat mosquitoes). He imported the flying mammals, but they promptly took off, leaving the tower empty.

The tower is in bad shape, and there's no access to the top.