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 ...

India's caves are thousands of years old. Some date back to the Stone Age. The earliest people to use caves were from the Mesolithic period. They lived in rock shelters and painted scenes from daily ...