Thailand's first national park, established in 2505, is a World Heritage Site in the year2548 by registering with 5 large forest is Khao Yai National Park. Pang Sida National Park Ta Phraya National Park Thap Lan National Park And Dong-Yai Wildlife Sanctuary. Regarded as a world natural heritage of the two.The forests of Thung Yai Naresuan - Huai Kha.