UK–based pool manufacturer Compass Pools has developed Infinity London, the world’s first building with a 360-degree infinity pool. Entirely made of cast acrylic, the 600,000-liter pool would cap a 55-story building, allowing swimmers a clear view of the city skyline, as well as the five-star hotel underneath.

Figuring out how guests would enter and exit the pool was, naturally, the major obstacle. Says technical director and designer Alex Kemsley, “Normally, a simple ladder would suffice, but we didn’t want stairs on the outside of the building or in the pool, as it would spoil the view—and obviously, you don’t want 600,000 liters of water draining through the building either.”

The solution recalls something out of a spy movie—based on the design of a submarine door, a rotating spiral staircase rises from the floor of the pool to create a portal.

A built-in anemometer will also monitor wind speeds, ensuring a comfortable temperature and preventing water from being sloshed onto the streets of London. Waste energy from the building’s air conditioning system will be reused to heat the pool.

Though partners and contractors have not yet been confirmed, construction on Infinity London could begin as early as 2020.

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