Khao Yai National Park is Thailand's first national park and one of the largest in the country, covering an area of over 2,000 square kilometres. This UNESCO World Heritage Site is renowned for its lush forests, stunning waterfalls, and abundant wildlife, including elephants, gibbons, hornbills, and even tigers. The park offers numerous hiking trails that cater to all levels, from easy walks to challenging treks. A visit to the iconic Haew Suwat Waterfall, made famous by the movie The Beach, is a must. For those interested in wildlife, guided night safaris are available, providing a unique opportunity to spot nocturnal animals in their natural habitat.