Buried for centuries, this hidden cellar is all that remains of London's medieval Whitefriars Monastery.

Never actually a tree at all, this spot was the site of London's public hangings for nearly 600 years.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

A quiet, semi-secret square with statues of Mahatma Gandhi, Virginia Woolf, and a conscientious objectors stone.

A Roman spa buried deep beneath the City of London.

East London art gallery showcasing contemporary art from Europe's Eastern Bloc.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

A unique tribute to the millions of animals who served and died for the British military.

It is still illegal to "quarrel" at this unlikely urban oasis built on top of an electrical substation.

This secluded walkway overlooks a magnificently wild London green space.

On a wall in linear London, a plaque hangs at the high water mark of one of the worst floods in fictional Kcymaerxthaereal times.

The secret wartime bunker built on the platforms of an abandoned Tube station.

London's only public statue of the much-married monarch adorns the gate to St Bartholomew’s Hospital.

A sculpture outside London's oldest cathedral honors the Mohegan chief who died while petitioning the king.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

A monument to the thrice mayor of London who according to lore made his fortune by selling his rat-chasing cat.

This overlooked street light once served as a KGB dead letter box.

The London statue that imitates passersby.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

Murals of the wild parties once held on the frozen River Thames.

The last remaining example of the boatmen's perches that once dotted the south bank of the Thames.

Three small rooms at the back of the “official” church of London's clowns.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

Shiny Brutalist box commemorates a pioneer of electricity and houses a railway transformer.