Son River and Catholic Church in the Phong Nha Ke Bang National Park, Quang Binh, Vietnam, Indochina, Southeast Asia, Asia

The illuminated interior of Paradise Cave in Phong Nha Ke Bang National Park, Quang Binh, Vietnam, Indochina, Southeast Asia, Asia

The illuminated interior of Paradise Cave in Phong Nha Ke Bang National Park, Quang Binh, Vietnam, Indochina, Southeast Asia, Asia

Sunset over the Son River in the Phong Nha Ke Bang National Park, Quang Binh, Vietnam, Indochina, Southeast Asia, Asia

Aerial of the Song Con River with the limestone mountains in the background, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Colourful Paradise cave, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Aerial of the Song Con River with the limestone mountains in the background, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Aerial of the Song Con River with the limestone mountains in the background, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Colourful Paradise cave, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Colourful Paradise cave, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

River boat on the Song Con River with the limestone mountains in the background, Phong Nha-Ke Bang National Park, UNESCO World Heritage Site, Vietnam, Indochina, Southeast Asia, Asia

Hang Son Doong, located in Phong Nha Ke Bang National Park, Vietnam, is home to a high quantity of rare cave pearls.

A caver stands in a sunbeam coming through an entrance to Hang En Cave in Phong Nha Ke Bang National Park, Vietnam. This natural phenomenon occurs only in the months of December and January.

A caver stands in a sunbeam coming through an entrance to Hang En Cave in Phong Nha Ke Bang National Park, Vietnam. This natural phenomenon occurs only in the months of December and January.

Cave explorers illuminate a large passage in Hang En, Phong Nha Ke Bang National Park, Vietnam.

A caver is dwarfed by massive stalagmites in Hang Son Doong. Light can be seen coming in in the distance through the frist doline which is over 3 km away. Hang Son Doong is located in Phong Nha Ke Bang National Park, Vietnam.

A cave explorer overlooks camp for the night from a high vantage point in Hang En, Phong Nha Ke Bang National Park, Vietnam.