This ancient Egyptian obelisk still bears the wounds of World War I.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

Hidden beneath the streets of London is a secret subway that only carried mail.

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

Victorian-era Londoners really wanted to believe this 17th-century cistern was actually an ancient artifact.

This Underground station has been a popular filming location for decades, even before it closed.

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

An unusual round church in London with a Templar past.

Once the largest town in eastern Yuba County now sits abandoned.

Overlooking Puget Sound sits a garden with a Buddhist prayer wheel and an elaborate labyrinth.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

A story of cutlasses carelessly carving a celibate centenarian's cemetery stone.

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

No one is sure what to do with this WWII shipwreck that sits at the bottom of the Thames, still loaded with tons of explosives.

This charming, narrow-gauge railway in the Thames Estuary is sometimes referred to as the "Train to Nowhere."

A perilous medieval road leading right into the sea.

This stretch of beach is the site of a prime watering hole and a primate watchtower.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Site of one of World War I's most horrific scenes.

A memorial to the soldiers who died in the bloody battles to control Verdun in World War I.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

One of the few standing Roman lighthouses and a labyrinth of tunnels are a couple of the secrets at this historic castle.

One of the oldest seagoing boats in the world can be found at the Dover Museum.

This Iron Age hill fort remained hidden until a series of storms revealed its history.