The Gherkin

30 St Mary Axe, previously known as the Swiss Re Building, is a commercial skyscraper in London's primary financial district, the City of London. It is nicknamed The Gherkin after the vegetable of the same name. It was completed in December 2003 and opened in April 2004. With 41 floors, it is 180 metres (591 ft) tall and stands on the sites of the former Baltic Exchange and Chamber of Shipping, which were extensively damaged in 1992 in the Baltic Exchange bombing by a device placed by the Provisional IRA in St Mary Axe, a narrow street leading north from Leadenhall Street.

After plans to build the 92-storey Millennium Tower were dropped, 30 St Mary Axe was designed by Foster + Partners and the Arup Group. It was built by Skanska; construction started in 2001.

The building has become a recognisable landmark of London, and it is one of the city's most widely recognised examples of contemporary architecture. It won the 2003 Emporis Skyscraper Award.

The building stands on the site of the former Baltic Exchange (24–28 St Mary Axe), which was the headquarters of a global marketplace for shipping freight contracts and soft commodities, and the Chamber of Shipping (30–32 St Mary Axe). The tower's topmost panoramic dome, known as the "Lens", recalls the iconic glass dome that covered part of the ground floor of the Baltic Exchange and much of which is now displayed at the National Maritime Museum. The Gherkin nickname was applied to the current building at least as early as 1999, referring to the plan's highly unorthodox layout and appearance.

On 10 April 1992, the Provisional IRA detonated a bomb close to the Baltic Exchange, causing extensive damage to the historic building and neighbouring structures. The United Kingdom government's statutory adviser on the historic environment, English Heritage, and the City of London's governing body, the City of London Corporation, were keen that any redevelopment must restore the Baltic Exchange's old façade onto St Mary Axe. The Exchange Hall was a celebrated fixture of the shipping market.

English Heritage then discovered that the damage was far more severe than initially thought, and they stopped insisting on full restoration, albeit over the objections of architectural conservationists. The Baltic Exchange and the Chamber of Shipping sold the land to Trafalgar House in 1995. Most of the remaining structures on the Baltic Exchange site were then carefully dismantled, and the interior of Exchange Hall and the façade were preserved, hoping for a reconstruction of the building in the future. The salvaged material was sold for £800,000 and moved to Tallinn, Estonia, where it awaits reconstruction as the centrepiece of the city's commercial sector.

In 1996, Trafalgar House submitted plans for the London Millennium Tower, a 386-metre (1,266 ft) building with more than 140,000 m² (1,500,000 sq ft) of office space, apartments, shops, restaurants and gardens. This plan was dropped after objections that it was totally out-of-scale in the City of London, and anticipated disruption to flight paths for both London City and London Heathrow airports; the revised plan for a lower tower was accepted.

John Prescott, the Deputy Prime Minister, granted planning permission on 23 August 2000 to construct a building on the site, which would be much larger than the old Exchange. The site needed development, was not on any of the "sight lines" (planning guidance requires that new buildings do not obstruct or detract from the view of St Paul's Cathedral dome when viewed from a number of locations around London), and had housed the Baltic Exchange.