Tham Kong Lo, also known as Kong Lo Cave, is a limestone cave in Phu Hin Bun National Park. Located on the Phu Hin Bun River, the cave has been described as a geological wonder of Southeast Asia. The karst cave is more than 6,5 km (4 miles) long and up to 91 meters (300 feet) high. It contains an emerald-colored pool that locals believe is sacred, saying it reflects the skin color of Indra, a Hindi god. Previous cave visitors praise a boat ride through the cave, calling it a grand adventure. A section of Kong Lo has now been atmospherically lit, allowing you a greater glimpse of this epic spectacle; your longtail docks in a rocky inlet to allow you to explore a stalactite wood of haunting pillars and sprouting stalagmites. Your imagination will be in overdrive as the boat takes you further into the bat-black darkness – you might liken it to Middle Earth (the lights of other boats like Gollum’s eyes swallowed in the gloom) or the Greek Underworld of Hades. Either way you won’t ever forget it. Be sure to bring a torch (flashlight) as the ones for rent are inadequate, and wear rubber sandals; the gravel in the riverbed is sharp and it’s usually necessary to disembark and wade at several shallow points.Staying in a private home is easy to arrange for those in need of overnight accommodations. The Tham Kong Lo Cave is well of the beaten path and one of the most spectacular secrets of Laos.
The months between November and March have the best sightseeing weather in the region of Laos.