Willis Building (London) 2004 and 2008 under the management of Mace and represented a significant addition to the City of London skyline, becoming its fourth-tallest building after Tower 42, 30 St Mary Axe and CityPoint. The core was topped out in July 2006 and the steelwork completed in September that year. Cladding began in July 2006 and the structure was externally completed by June 2007. It was internally fitted out and officially opened in April 2008. The building was the first in a wave of new tall towers for London's primary financial district. Others included The Pinnacle, the Leadenhall Building and the Heron
30 St Mary Axe designed by Norman Foster and Arup Group. It was erected by Skanska; construction started in 2001. The building has become a recognisable feature of London, and it is one of the city's most widely recognised examples of contemporary architecture. The building stands on the former sites of the Baltic Exchange (24-28 St Mary Axe), which was the headquarters of a global marketplace for shipping freight contracts and also soft commodities, and the Chamber of Shipping (30-32 St Mary Axe). On 10 April 1992, the Provisional IRA detonated a bomb close to the Exchange, causing extensive damage to the historic building