This abandoned gun tower was built to defend the River Thames from a French naval attack.

The Neolithic megalith was one of the first archaeological ruins protected by the British government.

This sculpture combines the literary Alice with her real-life inspiration.

This unassuming Victorian cemetery is the final resting place of author Lewis Carroll.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

An unusual ode to the late Irish playwright, complete with a squiggly bust and coffin-shaped bench.

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

More than a million titles fill the labyrinthine shelves of this prestigious private library.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

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

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This London marker celebrates the spot where the world-famous English band was founded.

The bronze uniforms commemorate the vital role of women during World War II.

This luxury shopping lane has been protected by its own tiny police force for over a century.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

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

The next-door homes of two very different musicians, George Frideric Handel and Jimi Hendrix.

Bronze sculpture celebrating the relationship between Churchill and Roosevelt.

The wooden telephone box hidden away in London's Piccadilly was the original prototype of the iconic kiosk.

A modern mechanical planetary system, part of a 10,000 year clock.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Eighty million natural history specimens call this gargantuan museum home.

A hands-off space for graffiti artists to hone and display their skills.