By Roderick Wayland Bates
Associate Professor, Nanyang Technological University, Singapore
Ratchaburi is a large, mostly agricultural province to the West of Bangkok, Thailand. It is dotted with highly eroded limestone hills, many of which contain caves, and many of which host Buddhist temples. One of these hills is at Wat Tham Mongkut, surrounded by fields of sugar cane. The hill here has a small cave (tham = cave) used as a Buddhist shrine. Up at the top of the hill, overlooking the temple, is a natural arch, clearly visible driving into the grounds, and even visible if you come along the main road from the North. Although there is no easy access to the arch, Martin Ellis of the UK’s Shepton Mallet Caving Club, who maintains a database of caves in Thailand, gives a span of 10 m (32 feet) and a height of 30 m (98 feet), while giving the hill a height of 100 m (320 feet).
At the right time of year, the rising sun shines directly through the arch. You can see a video of this on YouTube (it is five minutes long and changes very little throughout). A still from the video is below.