Aptly nicknamed “Snake Island”, the Ilha da Queimada Grande is home to around 4,000 venomous vipers – that amounts to approximately one snake per 10 square feet (1sqm). The bite of the golden lancehead (or Bothrops insularis), that can only be found here, is deadly. The Brazilian government has therefore banned visitors from the island. Only the navy is allowed to access it. Check out more abandoned islands the world forgot.