This limestone cavern, complete with stalactites, stalagmites, subterranean streams, and a 40-ft waterfall, is a rare find in the Caribbean. It is also one of Barbados's most popular attractions. The one-hour tours are on electric trams, which fill up fast; reserve ahead of time. Hard hats are required and provided, but all that may fall on you is a little dripping water. COST: $12.50.