Just under five hours northeast of Bangkok, this 837-square-mile (2,168-sq.-kilometer) spread is one of Thailand's top ecotourism draws, with extensive hiking trails and wildlife such as gibbons, macaques, sambar deer, bears, jackals, and elephants (one of the few areas left in Thailand where they survive in the wild). Read more about this and 10 of the country's other top draws on our recent post here.

(Nawit science)