30 St Mary Axe is a skyscraper in London's financial district, the City of London. It was formerly named the Swiss Re Building, after Swiss Reinsurance Company. The tower is also known as "The Gherkin". The building was finished in December 2003. It was opened at the end of May 2004. Swiss Re Tower has 41 floors. The tower is tall. It is on the site of the former Baltic Exchange, which was badly damaged in 1992 by the explosion of a bomb by the Provisional IRA.