Swimming pools between buildings and swimming pools on top of buildings are old news. But what about a swimming pool suspended between the tops of two buildings? Evidently, that will be a fixture at the luxury apartment complex Embassy Gardens in London. The developers called on aquarium designers to help build what they’re calling the world’s first “sky pool,” which will allow residents to swim across the gap between the two apartment buildings in a glass-bottomed pool 10 stories above ground. The glass will be about 8 inches thick. “The experience of the pool will be truly unique,” the CEO of the firm developing the project said in a statement. “It will feel like floating through the air in central London.” That idea sounds both amazing and kind of terrifying.