The Monument to the Great Fire of London, more commonly known simply as The Monument, is a 202 ft column in the City of London, at the junction of Monument Street and Fish Street Hill, 202 ft from where the Great Fire of London started in 1666 in Pudding Lane.
Following the Fire, Sir Christopher Wren was responsible for designing St Paul's Cathedral as well as 50 other churches in the City.
The Monument consists of a large fluted Doric column built of Portland stone topped with a gilded urn of fire, and was designed by Christopher Wren and Robert Hooke. The west side of the base of the Monument displays an emblematical sculpture, by Caius Gabriel Cibber, of the destruction of the City; with King Charles II, and his brother, James, the Duke of York (later James II) surrounded by Liberty, Architecture, and Science, giving directions for its restoration. It is the tallest freestanding stone column in the world. (Wikipedia)
Climb to the top for a unique view over the City of London
It has its own website
To the right of Tower Bridge is the oddly-shaped City Hall and HMS Belfast.
Cranes are just as much a feature of the London skyline as St Pauls. To its left is the BT Tower.
Apparently Magnus was not a Martyr, he was the victim of a 12th century political feud. However, be fair; "St Magnus the Martyr" sounds better than "St Magnus the Loser".