More photos of exploring Son Doong Cave in Vietnam. Take note of the height of the hikers in relation to the base camp, those tiny triangles at the bottom of the page. The cave, just discovered in 1991 but not thoroughly explored until 2001, is considered the largest cave ever discovered. It is...

All the equipment to make the journey -- headlamps, climbing gear, tents, food, amazing guides and paramedics -- were provided by the company that organizes the 3 night trek. The group size is limited to 15, the size of this MIT college reunion group. They work hard and play hard. I will be...

My son and his wife camped out for 3 nights in Vietnam's Son Doong Cave, thought to be the world's largest cave (in volume). The caverns could comfortably hold a 747 airplane. The cave has a river and a primaeval forest, and it has its own ecosystem. It was first discovered in 1990 but not...