Sai Yok was the site of a large Japanese army barracks and POW labor camp during World War II. The 190-sq mile (500-sq km) national park was established in 1980 and today is renowned for its tranquil river scenery and the impressive Sai Yok Yai waterfall, which tumbles into the Khwae Noi River near to the park headquarters.
Accommodation is available in park bungalows or on pleasant houseboats, and boats can be chartered – at some expense – to some nearby caves. The caves are home to the 1-inch (3-cm) long Kitti’s hog-nosed bat, considered by some to be the world’s smallest mammal, and which was discovered in 1973 by Thai naturalist Kitti Thonglongya.
The Burma-Thailand Railroad Memorial Trail, south of Sai Yok, pays tribute to prisoners who died during the excavation of the Konyu railroad cut. Near to the cut, which was given the name “Hellfire Pass” by the many prisoners of war who labored through the night by torchlight, was the “Pack of Cards Bridge.” This rickety 985-ft (300-m) long, 82-ft (25-m) high structure was built at perilous speed with green timber and, as a result, heavy loss of life – the structure collapsed three times during its construction.
The trail, set up with funding from the Australian government, winds up to Konyu cutting through a bamboo grove. The railroad track has long since been removed.