This building has been known by many names: The Commercial Union Tower, Aviva Building, the St Helen's Building and at the time of writing, it was known as the Aviva Tower. It was originally one of two structures sharing the same piazza, but the other building - the adjacent P&O building to the south west - has since been demolished. Completed in 1969, it was the first building in London, at 118m and 28 floors, to exceed the height of St Paul's Cathedral. It was totally reclad following the detonation of a terrorist bomb across the road in 1993, but the influence of Mies' Seagram Building is still evident in the detailing of the envelope. All the floors are suspended off the central concrete core in two groups of 12, via perimeter hangers to produce a column free interior, with the suspension structure occupying the central and upper plant zones.