Khao Yai National Park.

As Thailand’s oldest national park, Khao Yai spans over 2,000 square kilometers of UNESCO-listed monsoon forest and grassland, offering some of the country's best wildlife viewing just a few hours from Bangkok. The park is a sanctuary for wild elephants, gibbons, gaur, and hornbills, with night safaris and guided treks providing close-up encounters. Beyond the fauna, Khao Yai is defined by its dramatic hydrology, featuring the towering Haew Narok waterfall and Haew Suwat, famously depicted in the film *The Beach*. Visitors can navigate over 50 kilometers of hiking trails, climb to scenic viewpoints like Khao Rom, or gather at dusk near the park’s boundary caves to watch millions of wrinkle-lipped bats stream into the sunset sky in a spectacular, continuous cloud.