Highlights of the five-night trip include seeing the cave’s own rainforest and a calcite wall called the Great Wall of Vietnam. Vietnam is home to the world's largest cave. It's so vast that it has ...

Imagine the surprise of young lumberjack, Ho Khanh, a native of Vietnam's then-sleepy Phong Nha township, when he saw enormous, ethereal columns of fog billowing out of the ground, like the earth ...