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

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

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

The commemorative stone column conceals a secret laboratory.

The Great Fire of London and the regulation of one-way streets both started in this alley.

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

The ritual has been performed uninterrupted for nearly 700 years.

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

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

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

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

An architectural oddity hides in plain sight on this iconic London bridge.

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

These medieval tunnels provided water to the city above through centuries of civil war and plague.

An ancient fortification lives on in this Chinese city.

The most famous location in China was home to whole dynasties worth of imperial rulers.

This Tang Dynasty behemoth is the biggest Buddha in the world.

The once highest point in China blends symbolic design with a kick of adrenaline.

Home of the world's largest crocodile.

A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

After much poking and prodding, this island is decidedly not a magnetic anomaly, but it sure is pretty.

Peanut butter trees and miracle berries are just the beginning.

WWI hospital ship lost in a cyclone turns up on the coast of Fraser Island, where she remains rusted and forgotten.

The only pollutant in the clear blue water is sunscreen.