Normally if your yacht goes underwater, it's a disaster. With the Migaloo Submersible Yacht, it happens all the time. This incredible watercraft combines the luxury of a yacht with the underwater capabilities of a U.S. Navy submarine. It comes in five models, ranging in size from the 72-meter M2 to the massive, city-like 283-meter M7. Each is built to military safety standards, uses a modern acrylic pressure hull for a wide-open interior space, offers incredible views of the ocean, and is one of the most private spaces you can find — after all, not many people are going to be looking for you under the surface of the water. Best paired with one of the company's Kokomo private floating habitats.