Scattered throughout London are ancient remnants of the city's former bounding wall.

An incarceration museum on the spot of possibly the oldest prison in England.

This one has sailed five times as far as Sir Francis Drake's famous ship.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

This South London cemetery holds the remains of more than 15,000 people.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Before becoming a poet John Keats studied here to become a surgeon.

This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

The fences outside some of South London's estates are made from recycled World War II stretchers.

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

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

"We gonna rock down to Electric Avenue, and then we'll take it higher..."

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

Abstract dinosaur models in London.

A monolithic monument in Greater London.

The Origin of On the Origin of Species.

These morbid carvings remind churchgoers of the inevitability of death.

A vast overgrown cemetery, once known as one of London's "Magnificent Seven."

A sculpture of a famous ape who was once a beloved household name in London.

The remains of Crystal Palace Great Exhibition of 1851.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.