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

An unusual round church in London with a Templar past.

Once thought to be the mysterious work of a witchy prophetess, a well with unusual properties turns objects into "stone".

The remains of a remote village that once housed over 1,200 dam workers and their families.

A steep and winding road in the Yorkshire Dales passes by these deep natural potholes.

This incredible viaduct was part of the Victorian railway boom and helped the Midland Railway navigate tough terrain.

This charming English house was once the home of England's most famous poet.

These Roman ruins in England’s Lake District are 2,000 years old, but look pretty good for their age.

Scotland's oldest medieval bridge is also among the last reminders of early medieval Aberdeen.

The heart of a Scottish legend had a centuries-long journey before reaching its final resting place.

The beloved war-time celebrity spent time in the area before retiring to the Edinburgh Zoo.

Twice a day this ancient path disappears with the tides, leaving the Holy Island of Lindisfarne out to sea.

The medieval-looking hammer beam teak roof may be a Victorian vanity, but it's still absolutely magnificent.

This slowly crumbling mansion was home to one of East Africa's richest and most powerful slave traders.

This beehive tomb built for royalty sat hidden for over 3,000 years.

Every spring, locals see the shadowy figures of a ghost army of slain Greek soldiers descend upon this ruined fort.

This famous archeological mystery may be an ancient example of movable type.

This restored eighth-century palace is a shining example of ancient Umayyad architecture.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Commonly acknowledged as the only public monument to the Devil himself.

A lush indoor jungle fills this bustling Madrid transportation hub.

An iconic and controversial ancient Iberian funerary urn with a hauntingly penetrating gaze.

This enigmatic artifact is a rare depiction of an ancient Iberian noblewoman.

This colorful colonial neighborhood in Panjim is one of the only Latin Quarters in Asia.