With verdant forests, gushing waterfalls, flocks of macaques, wild-gibbon calls, wandering elephants, and even the promise of a glimpse of a tiger or clouded leopard, the Khao Yai National Park is easily one of the best wildlife spots in Thailand. Tours are extremely easy to organise via agencies in the closest town which is either Bangkok or Pak Chong. A tour will usually include an exciting waterfall swim and light treks. A top tip to consider is to bring plenty of insect repellent and to wear trousers tucked into long socks, as the forest undergrowth is rife with leeches.