The Canary Wharf Tower was the highest building in the UK when it was built in 1991: at 243 metres (around 800ft) tall, it's visible from most high points in London. It's made of glass and steel cladding, weighs in at a chunky 1,000,016 kg, and was designed by Cesar Pelli Associates. The skyscraper's roof is topped by a glass pyramid, which catches the light on sunny days, and is lit up at night with a flashing beacon. As an icon of the city, it symbolises Thatcher, yuppies, and the days of big money and empty investment. See salimfadhley's excellent wu for more on Canary Wharf.