Nelson's Column, in Trafalgar Square. The square was laid out in the present design in 1840, by the architect Charles Barry. It commemorates the 1805 naval battle of Trafalgar, in which the British, under Admiral Nelson, destroyed Napoleon's battlefleet.
Cape Trafalgar is a headland in southwest Spain, lying between the Strait of Gibraltar and Gulf of Cadiz.
The domed building in the background is the National Gallery.