Snake Island

"The highest concentration of one of the most venomous snakes in the world is located about 90 miles off the coast of Santos, Brazil, on a small, craggy chunk of otherwise uninhabitable land. It's known as Ilha da Queimada Grande, or Snake Island, and it's the only place you will find 2,000 or so of the wholly unique golden lancehead viper, or Bothrops insularis."