Ilha da Queimada Grande, Brazil, Where One Bite Can Kill You
Everyone calls it Snake Island. The small forested outcrop off Sao Paulo state holds the highest density of venomous snakes measured anywhere on earth, an estimated 2,000 to 4,000 golden lanceheads whose venom is several times more potent than that of their mainland relatives. Untreated bites are reported to kill roughly seven percent of victims, and the nearest hospital is a boat ride away. The Brazilian Navy closed the island to civilians in the 1920s and still controls it, maintaining the lighthouse and turning boats back. Only researchers land, and only with a federal scientific permit, usually a handful of trips a year by herpetologists from the Instituto Butantan, with a doctor and antivenom aboard. Going ashore without one means prosecution for entering a protected reserve, and that is the least of the risks waiting in the leaf litter.