The planet is warming, which is causing glaciers and ice sheets to melt and Earth's sea levels to rise. As the ocean makes inroads over the next century, people living in low-lying areas will be displaced, leaving them in need of new homes. Don't let memories of "Waterworld" deter you from checking out these innovative marine dwellings. Whether you're concerned that your home will be soon be beachfront property, or you've simply always wanted to live life at sea, you don't want to miss these groundbreaking (water-breaking?) designs.