The Roman Amphitheatre beneath Guildhall

The Guildhall is a municipal building in the City of London on Gresham Street. While the current building dates from the 15th century, documentary evidence suggests a guildhall has existed at this site since at least the early 12th century. It remains the ceremonial and administrative centre of the City of London and its Corporation.

During the Roman period, this site was home to the London Roman Amphitheatre, which was the largest in Roman Britain. Partial remains of the structure are on public display in the basement of the Guildhall Art Gallery, and the outline of the arena is marked with a black circle on the paving of the courtyard. Excavations have shown that a 13th-century gatehouse was built directly over the southern entrance to the amphitheatre, suggesting the Roman structure influenced the layout of the surrounding buildings.

Legend describes the site as the location of the palace of Brutus of Troy, who is said to have founded a city here known as New Troy. The building continues to host many events, including the Lord Mayor's Banquet where the Prime Minister makes a major world affairs speech. The complex also houses the Guildhall Library and includes a North Wing designed by Giles Gilbert Scott and a West Wing built in a modernist style.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons