Hidden away in Khao Sam Roi Yot National Park, the Phraya Nakhon cave and throne pavilion is one of the most unusual and spectacular sites in Thailand. The throne room structure was built inside a huge cave with a massive hole in its roof that lets sunlight flood in at certain hours of the day. You need to catch it at just the right time, after hiking a steep, slippery route to reach it -- but what a reward! The scene looks straight out of a movie like "Raiders of the Lost Ark" or "Avatar." Visitors report that the best time for viewing is from November to February between 10:30 and 11:30 a.m. If weather conditions are good, it's possible to take a boat part of the way. From that point, it's about a 1,400-foot climb to reach the cave.

Aside from Phraya Nakhon, there are plenty of other things to see at this marine national park. Birders will love the park's wetlands, where you can take a boat to search for egrets, cormorants, herons and kingfishers. Hikers can trek for great mountain views. There are also beaches for lounging. The park is located in the Prachuap Khiri Khan province, about an hour's drive south of the resort area of Hua Hin.