There are some pretty cool hotel pools out there, but this new infinity pool in London might top them all. The 600,000-liter pool will sit atop a new 55-story building, and the designers claim the concept is a world first. It’s “the only building in the world to incorporate a 360-degree infinity pool,” says Compass Pools. Situated atop a planned five-star hotel, the pool will be made from cast acrylic and have transparent sides and floors, so people in the floors below will be able to see swimmers above them.

Perhaps one of the most unique features of Infinity London is that there are no stairs on the outside of the pool, or the building, raising some questions about how swimmers are supposed to access it.

“We faced some quite major technical challenges to this building,” the design firm said, “the biggest one being how to actually get into the pool. The solution is based on the door of a submarine, coupled with a rotating spiral staircase which rises from the pool floor when someone wants to get in or out — the absolute cutting edge of swimming pool and building design and a little bit James Bond to boot!”

The pool will also have a built-in anemometer to monitor wind speed and be linked to a computer-controlled building management system to ensure that the pool’s temperature remains perfect (and doesn’t spill over the edge). The pool will be heated by waste energy from the building’s air conditioning system, making it pretty sustainable too.

If all goes well, construction of the pool will begin in 2020.

H/T: CNN