
Name: Snake Island
Location: Atlantic Ocean off the coast of São Paulo state, Brazil
Coordinates: -24.484043070527676, -46.67561478998516
Why it's incredible: The island is so dangerous, only the Brazilian navy and scientists with special permits are allowed access.
Snake Island is a small, forested island off the coast of Brazil that writhes with thousands of venomous vipers. The snakes, which grow up to 3.9 feet (1.2 meters) long, are golden lancehead pit vipers (Bothrops insularis). They are so venomous, the Brazilian navy has closed the island to the public since the 1920s.