It's rebuilt every winter in northern Sweden, only to melt away in the spring. Yet that impermanence is part of the appeal. Built with two-ton blocks of ice from the nearby Torne River, the Icehotel is the result of collaborations between artists and engineers, who work together to create the arched hallways, unique rooms, and ornate reception areas. Since it stays around 23 degrees inside, guests are outfitted with warm outer clothing and Arctic sleeping bags for their bed. Warm accommodations are also available, as is an ice chapel and ice bar, and thanks to a solar-powered addition, part of the hotel will now be able to operate year-round, giving even more people a chance to spend a night on ice.