The Mayans in Belize viewed caves as spiritual sites, as they were thought to be portals to the Underworld. Visitors to the caves will find the skeletal (some human!) and pottery remnants of sacrifices offered by religious leaders to their gods. Don't want to just sit out the dying of the light? Try the popular Actun Tunichil Muknal cave tour, during which you don a hard hat and headlight while hiking, swimming and wading your way to an interior cavern featuring full human skeletons like the Crystal Maiden, whose calcified remains sparkle in the light.

-- Recommended by Erica Silverstein, Features Editor, Cruise Critic

The Art of Slow Travel