[Lee Stewart]

Infinity pools are a staple of beachside resorts and high-end hotels - but you probably haven't seen one quite like this. Compass Pools is planning to build a borderless pool at the top of a 55-story London skyscraper providing a 360-degree view of the city skyline.

But there's just one problem. People are confused about how you're supposed to enter and exit the pool.

Compass Pools' website says that swimmers will use a spiral staircase "based on the door of a submarine" that rises from the pool's floor. Alex Kemsley, swimming pool designer and technical director for Compass Pools, told Business Insider sister site INSIDER that the staircase works like "a tube in a tube."

"The first tube is to cut a path through the water and create an airlock," he said. "The second to deliver the staircase up to water level."