Staying here is an experience of a lifetime—if you’re up to taking the plunge. Built as a research lab, this underwater habitat, which rests on pillars on the seabed, now operates as a pricey two-room hotel most popular with diving honeymooners. To get inside, guests swim 21 feet under the structure and pop up into the unit through a 4[ts]6-foot “moon pool” that gurgles soothingly day and night. The 30-foot-deep submarine suite consists of two separate bedrooms that share a common living area. Room service will deliver your meals, newspapers, even a late-night pizza in waterproof containers, at no extra charge. If you don’t have the time, desire, or budget to overnight, you can hang out in the lodge for 3 hours for $150 per person.