Sung Sot Cave (Cave of Surprises)

What many visitors may not know about UNESCO World Heritage Site Halong Bay, just outside of Hanoi, is that the bay itself isn’t the area’s only attraction. The limestone karst formations of the bay look impressive from the outside, but many of them are just as impressive from within. Sung Sot Cave, or the Cave of Surprises, is the best known cave of Halong Bay and one of the most spectacular.

Located on Bo Hòn Island, the Cave of Surprises was first discovered by French explorers in 1901. Covering an area of more than 130,000 square feet (12,200 square meters), the massive cave consists of three smaller compartments, or “rooms,” each filled with impressive stalactite formations. In places, the grotto’s roof sits nearly 100 feet (30 meters) from the cave floor.

The grotto has been outfitted with a smooth walking path and is colorfully lit throughout, though you will have to climb a series of stone steps to reach the cave’s entrance.