Window cleaners Lee Mason (left) and Paul Wright (right) pause for a break in their cleaning gondola outside the 50th floor of the One Canada Square skyscraper on Feb. 8 in London. Currently the tallest building in Britain, it lies at the heart of Canary Wharf, the business and shopping district on the River Thames. To clean all the windows of the building takes a month, with the cleaners suspended up to 190m from the ground.