I’m not sure why I hadn’t realised you could actually go inside Wellington Arch until my most recent visit to London. It’s now an English Heritage property, built as an original entrance to Buckingham Palace but then became a victory arch celebrating the Duke of Wellington’s defeat of Napoleon. The sculpture at the top, apparently the largest bronze sculpture in Europe, represents the Angel of Peace descending on the four-horsed Chariot of War.
Inside you can go either up the stairs or by the lift to several floors of exhibitions about the building and about Wellington. The Arch was built in 1825-7 but moved to its current position in the 1880s, the bronze sculpture above not being placed there until 1912.
And even better you can go onto the balcony of the arch, one on either side, to get some lovely views of the area.