Description 5 oclock and the city boys go home.Looking East on Throgmorton Street at the setting sun reflecting off Tower 42.Tower 42 is the tallest skyscraper in the City of London and the fifth tallest in London as a whole. It was originally built for the National Westminster Bank (NatWest), hence its former name, the NatWest Tower.It is 183 metres (600 ft) high, which made it the tallest building in the UK until the topping-out of One Canada Square in Docklands in 1990.