Coles Cave in Saint Thomas, Barbados is a natural cave system that offers a unique adventure experience. It's known for its steep descent into a narrow entrance, a dark interior, and underground streams, says Barbados Pocket Guide. The cave's interior is described as a subterranean chasm with varying dimensions and branches, and its full extent remains unknown. Visitors can explore the cave with flashlights, walking up the river and enjoying the natural formations.