Residents of a new apartment complex in South London will be able to swim from one building to the next, ten stories in the air, with uninterrupted views of the surrounding city. The glass-bottomed swimming pool suspended between two towers is billed as a ‘world’s first,’ spanning 90 feet without any visible structural supports.

Looking up from ground level, the pool resembles something of a human-sized aquarium, with swimmers visible to passersby from virtually all angles. It’s not clear how thick the glass will have to be in order to support the weight of that much water, or how the pool will hold up in inclement weather.

“My vision for the sky pool stemmed from a desire to push the boundaries in the capability of construction and engineering,” says Sean Mulryan, CEO of construction firm Ballymore Group. “I wanted to do something that thad never been done before. The Sky Pool’s transparent structure is th result of significant advancements in technologies over the last decade. The experience of the pool will be truly unique, it will feel like floating through the air in central London.”

The pool is part of a rooftop relaxation area at the Embassy Gardens Legacy Buildings, a 2,000-unit complex that will also feature a gym and a ‘work from home’ office area. Located in London’s new Nine Elms quarter, the buildings are under construction now and expected to be complete by 2017.