The Phraya Nakhon cave is situated in Khao Sam Soi Yot National Park, outside Hua Hin, a beach town about 2½ hours outside Bangkok. To get there, you take a 45 minute (more or less) hike over a hill and along a beach, and then another half hour up a hill to get to the cave.
The cave consists of two limestone chambers, both of which are open to the sky. In the second one is the Kuha Karuhas pavilion, built by King Rama V some time at the end of the 19th century.
|Inside the first chamber, looking up.||The “Bridge of Death.”||Kuha Karuhas pavilion.|
A website I read advised visitors to get there by 11:00 am to get the best light, and we just made it.