You’ve seen all there is to see of Mekong under the sky; what about seeing what’s below ground? The karst (limestone) landscapes of some out-of-the-way parts of the Mekong Sub-Region hide secret caverns that now serve as holy places, historical hiding haunts, and physical challenges for brave visitors.
In Laos, the rugged karst mountains of Khammouane hide a collection of exquisite caves, of which Kong Lor Cave is one of the most popular. Its size alone puts it on top of any must-visit list: Kong Lor stretches some 7.5 kilometres long, its widest sections reaching over 100 meters in height and 90 meters from wall to wall.
A seven-kilometer underground river runs through Kong Lor; you can ride a motorized long-tail boat deep inside, with only your boatmen’s headlamps to cast any light, you’ll stop at a gigantic chamber where lights place the assorted stalagmites, stalactites, columns, and other cave formations in stark relief.
The cave can be found in Phou Hin Bun National Park. The dry season from October to May is the best time to visit. Exploring the cave during monsoon season can be dangerous; at the height of summer, low water levels mean you may need to occasionally get off the boat and push.
In Cambodia, the city of Kampot is a launchpad for spelunkers who want to explore the nearby caves; they’re small relative to some of the giants you’ll find in the rest of the Mekong, but they’re still scenic and positively historic.
The most famous one in the area, Phnom Chhnork, has been repurposed for worship. A temple was built inside in the 7th century, and dedicated to Shiva. Beyond the millennium-old brick structures inside, you’ll also find elephant-shaped limestone formations, and a second cave system that calls for some climbing skill (and an utter lack of claustrophobia) to reach.
In Yunnan, People’s Republic of China, an expansive cave system awaits tourists in Luxi County, some 160 kilometers from Kunming. The Alu Ancient Cave contains three distinct caves (Luyuan Cave, Yuzhu Cave, Biyu Cave) and the Yushu River that runs 800 meters through the system.
Tourists can explore a three-kilometer tour route that covers several caves that showcase the most starkly beautiful formations within. The limestone formations look like a stone god’s fever dream, with some resembling curtains, bamboo shoots, and flowers. Locals have given them evocative names, such as “Flying Dragon Playing Waterfall”, “Three Elephants Running Quickly in the Plain”, and “Old Tortoise Enjoying the Moon”.
To get here, visitors can take shuttle buses from Kunming, then catch a taxi from Luxi county to the cave entrance. The caves are open to tourists from 6:30am to 6pm; best months to visit are from March to April, and from September to December.