Ludgate Hill is a hill in the City of London, near the old Ludgate, a gate to the City that was taken down, with its attached gaol, in 1780. It is the site of St. Paul's Cathedral, traditionally said to have been the site of a Roman temple of the goddess Diana. It is one of the three ancient hills of London, the others being Tower Hill and Cornhill. The highest point is just north of St. Paul's, at 17.6 metres (58 ft) above sea level.
Ludgate Hill is also the name of a street which runs between St. Paul's Churchyard and Ludgate Circus (built in 1864), from where it becomes Fleet Street. It was formerly a much narrower street called Ludgate Street.
The Wikipedia page is [1]