Nestled deep within Thailand’s Khao Sam Roi Yot National Park, almost 300 kilometres south of Bangkok, the Phraya Nakon Cave is one of the most exquisite caves in Thailand and definitely one of the most photographed. The main attraction is the Kuha Karuhas pavilion located inside the Phraya Nakhon. The pavillion was built by King Chulalongkorn (Rama V) in the 1890, when he visited the place and fell in love with its beauty. Later, King Prajadhipok (Rama VII) and the present King of Thailand, King Bhumibol Adulyadej (Rama IX) also visited the cave. The main chamber contains the signatures of both King Rama V and King Rama VII on the wall.
The cave can be reached on foot from Laem Sala beach inside the park. The up hill path leading to the cave is steep and rough. It’s long – about 430 meters – but along the way there are rest stops where you can take a breather and enjoy the view of the sea below from the top.
Phraya Nakhon is actually two sinkholes whose roof has fallen in, illuminating the cave with sunlight, especially in the morning. This is the best time to visit the cave. The cave was named for Phraya Nakhon, ruler of the city-state of Nakhon Si Thammarat, who inadvertently discovered it over 200 years ago when a gale forced his ship ashore.
Source