30 St Mary Axe nearly oblivious to the tower's existence until directly underneath it. The building was constructed by Skanska, completed in December 2003 and opened on 28 April 2004. The primary occupant of the building is Swiss Re, a global reinsurance company, which had the building commissioned as the head office for its UK operation. The tower is thus sometimes known as the Swiss Re Building, although this name has never been official and has more recently fallen out of favour, since the company's main headquarters is in Zurich and the Gherkin name has become more popular. The building uses energy-saving methods which
30 St Mary Axe not recoverable, forcing them to relax their building constraints; they hinted that an "architecturally significant" building might obtain a favourable reception from City authorities. This gave the architect a free hand in the design; it eliminated the restrictive demands for a large, capital-efficient, money-making building, whose design was per the client's desire. The new building's low-level plan satisfied the planning authority's desire to maintain London's traditional streetscape, with its narrow streets. The mass of the tower was not too imposing. Like Barclays Bank's former City headquarters in Lombard Street, the idea was that the passer-by in neighbouring streets would be