Plans to build a rooftop infinity pool with 360-degree views of London are underway.
Compass Pools, responsible for the design, said the 600,000-litre pool would be built on top of a 55-storey building, allowing visitors to float on the city's skyline.
The building beneath will be a 5-star hotel where guests can look up to the pool through its transparent bottom.
The infinity pool will need a built-in anemometer to monitor wind speed and a system to control water temperature and make sure water is not blown down to the streets below.
The water will be heated using waste energy from the building's air-conditioning system.
Swimming pool designer and technical director for Compass Pools Alex Kemsley said he wanted to design the pool first before creating the building underneath it.
"Architects often come to us to design rooftop infinity pools, but rarely do we get a say in the building design because the pool is usually an afterthought," he said.
"But on this project, we actually started with the pool design and essentially said, 'how do we put a building underneath this?'
"When we designed the pool, we wanted an uninterrupted view, both above and below the water.
"With a 360-degree view of London from 220 metres up, it really will be something else — but it's definitely not one for the acrophobic."
Mr Kemsley also said there were major technical challenges with getting people into and out of the pool.
"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 litres of water draining through the building either."
"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 building's exact location is yet to be confirmed.
Construction will kick off in 2020 "if all partners and contractors are confirmed", according to the company's website.