This is the world's first 'floating' sky pool with a glass bottom. Set to open in London next month, sky pool stretches across a 46ft gap between two blocks of luxury flats. Located in Nine Elms in south-west London, the transparent pool is 82ft long and is a breath-taking 35 metres above the ground. Only residents of the building and their guests will be able to use the pool, including the buildings' luxury sky deck which also includes a spa, summer bar and orangery.