Visit secret spaces, from the hospital that performed the world’s first successful Caesarean to the city’s only Roman baths

Admiralty Arch. During a royal coronation, wedding or funeral, you will often see a procession pass under Admiralty Arch. The Grade l-listed building, completed in 1912, is at the opposite end of Buckingham Palace. Look closely at the inside of the northernmost arch and you will see a curious thing: a nose poking out of the wall. Rumour had it that it was put there in honour of the Duke of Wellington, who was known to have a large nose. In fact, it was created by artist Rick Buckley to complain about the country becoming a nosy, CCTV-reliant society.

‘Nazi Dog’ Burial Place. There is only one memorial to a Nazi in the country: Giro the dog’s grave. German ambassador Leopold von Hoesch lived in Carlton House, just off The Mall. In 1934, his dog, an Alsatian, was accidentally electrocuted. Hoesch buried his beloved pet in the back garden, and the grave can be peered at by visitors. The epitaph reads: ‘A faithful companion.’