Guildhall was the former residence of the Lord Mayor.

Guildhall, administrative centre of the City of London. Within its halls are the offices and meeting rooms of the Corporation of London and its Court of Common Council, which is the body responsible for governing the City and for defending its interests throughout the London metropolitan area. The Court of Common Council meets in the Great Hall, which is more than 150 feet (46 metres) long and some 50 feet (15 metres) wide.

A meeting hall may have existed on the site in the early Middle Ages, and it is known that a Guildhall was erected there in the early 15th century. Although that structure was largely destroyed in the Great Fire of London in 1666, its 15th-century crypt remains intact. By 1673 the Guildhall was rebuilt. It burned again in 1940, during a bombing raid, and a new roof and additional chambers were subsequently built.

The Guildhall Library contains extensive references on the history of London, including original maps, prints, and registers. Also, of interest is the Guildhall Library Clock Room, featuring the collection of the London Clockmakers’ Company, which was chartered in 1631. Between 1987 and 1988 archaeologists working on the grounds of the Guildhall uncovered remains of the city’s Roman amphitheatre, this discovery provided the impetus for further excavations in the surrounding district in the 1990s.