Bored of doing lengths in your local swimming pool?
Why not take things up a level — 55 levels, to be precise.
The world's first rooftop infinity pool is set to be built on top of a skyscraper in London, meaning you could enjoy 360-degree views of the capital while working on your breaststroke.
Or, more realistically, posing for pictures.
The proposed Infinity London tower would be 55 stories tall, with a 600,000-liter pool on top.
The pool, designed by Compass Pools, would grace the top of the skyscraper, 200 meters high in the sky — though where exactly the building will be is still to be decided.
The sides of the pool would be made from cast acrylic rather than glass, as the former transmits light at a similar wavelength as water, enabling the pool to look perfectly clear, Compass Pools said on its website.
The floor of the pool would also be clear, meaning swimmers could see and be seen by visitors below.
The designers are also proposing a built-in anemometer to monitor the wind speed, to make sure the water stays at the right temperature and isn't blown down to the streets.
It's a sustainable plan too, designed to use waste energy from the building's air-conditioning system to heat the pool — and this being London, it'll certainly need to be heated.
As the sun sets, the pool's lights would create "the appearance of a sparkling jewel-topped torch" at night, Compass Pools said.
But one major question most people have is: How on earth do you get in and out of the pool?
"Swimmers will access the pool through a rotating spiral staircase based on the door of a submarine, rising from the pool floor when someone wants to get in or out," Compass Pools said, adding that stairs on the outside of the building were avoided because they would spoil the view.
We asked for more information.
"With regards to the staircase, you have to imagine a tube in a tube," Alex Kemsley, Compass Pools' pool designer and technical director, told INSIDER.
"The first tube is to 'cut a path' through the water and create an airlock. The second to deliver the staircase up to water level.
"It's controlled by a PLC (programmable logic controller) that are used in the industry to automate the process and ensure that all valves and locks can only operate at the right time. The engineering is complex but delivers the seamless look."
The staircase would rise up in one corner of the pool (you can see the outline of a circle in the bottom-right corner of the picture above) from the floor below, which would be used for changing rooms and services.