The Monkey Island of Homosassa
This one is literally the result of monkey business; no lie. Originally not an island, but a rocky outcropping, a local developer instructed his crew members to throw some dirt on the rock pile to keep boaters from bottoming out. Instead of doing a little, they covered the outcropping with enough earth to make it an island. So the developer thew a lighthouse and trees on his new island, and then focuses on a wildlife park he was building up the river. The park was to have all sorts of exotic animals and plants, including a group of former medical research monkeys.
These primates, however, were notoriously obnoxious and skilled escape artists. They kept on getting out of their cages, stealing from tourists, knocking down kids and biting people, it was decided that they needed to go. Suddenly, the developer remembered his little lighthouse island, and decided it’d be the perfect monkey Alcatraz.
Three spider monkeys and two squirrel monkeys were dropped off on the island, with upgraded trees and shelter and became a local attraction, that 40 years later still draws people in.