Cherrapunji
A well-lit limestone cave system you can walk through in about 30 minutes, Mawsmai is the most accessible cave near Cherrapunji and gives you a vivid sense of the karst geology that defines this entire plateau. Narrow passages open suddenly into cathedral chambers, stalactites hang within arm's reach, and the cool damp air inside is a sharp contrast to the misty plateau outside.
The cave passages get very narrow in places — not ideal if you are claustrophobic. Wear old clothes since the walls are wet and muddy in sections.