#17 Morgan Island, USA
Rhesus monkeys are known to anybody who has taken a biology class. However, their name is synonymous with something else completely in the USA.
Morgan Island is home to lots of Rhesus monkeys that were shipped over from Puerto Rico. While this would ordinarily be a source of joy, the monkeys are said to be infected with Herpes B Virus.
They were initially shipped over because they were infecting the native population. Now, they have inhabited Morgan Island. Visitors are not allowed for safety reasons.
Researchers themselves require special permits to enter the island.
Morgan Island is affectionately known as Monkey island since the monkeys themselves have free run of the place. Tourists are not allowed near the island for fear of infection.