TRAFALGAR
Trafalgar Square (Charing Cross tube station) is the place where most distances to London are measured to. It's generally considered the centre of the London urban area, at the junction between the West End to the north and west, central Westminster to the south, and The City to the east.
Named after the cross erected here at the end of the 13th century, in memory of Queen Eleanor, Charing Cross was originally the area around the junction of Whitehall, The Strand and Cockspur Street. The Mall and Northumberland Avenue later were built to meet the junction. In the early 19th century, the area to the north was converted into Trafalgar Square, making a larger junction that also included Charing Cross Road, Duncannon Street and Pall Mall.
After WW2 Trafalgar Square became a large roundabout, this was changed in the '00s, when, to lower traffic speeds and allow better pedestrian flows, the north side of Trafalgar Square was closed, the other sides converted to two-way traffic, with a roundabout being constructed at Charing Cross, immediately in front of Trafalgar Square.