One of London's lost rivers runs through a pipe over the tracks of this subway station.

This statue of one of the engineers who created the London Underground hides a ventilation shaft for the tube lines that run under the street.

The first regular high-definition TV transmissions were made from this seemingly out-of-place mast located on one corner of a Victorian-era entertainment venue.

This sculpture of a pylon is upside down and askew, as if its main purpose is to confuse passersby.

A bit of the Berlin Wall was gifted to the Icelandic capital to commemorate the 25th anniversary of German reunification.

These concrete domes were installed on an Icelandic bluff to honor a very specific musical tradion.

An isolated, rusty phone booth commemorates Iceland's first international telegraph cable.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Greenland's first shopping mall also hosts the country's government.

The bones of the Biblical Magi traveled to Constantinople and Milan before landing in their current home inside an elaborate golden reliquary in the Cologne Cathedral.

The location of this small park was once the site of an infamous public morgue.

A historic and beautiful Art Nouveau chamber in a historic railway station.

A museum dedicated to Norwegian music, old and new alike.

Montmartre's sole surviving windmill became an iconic landmark for 19th-century painters, artists, and bohemians.

This ancient causeway can flood daily, leaving Mersea Island as a true island for hours at a time, and cutting its 7,000 residents off from the mainland.

Many mysteries surround these objects questioning whether they are cannonballs at all.

Third time's a charm, or in this case, two testicles are.

These post boxes from a bygone era have been the source of controversy and debate.

The largest Victorian water tower in Britain.

On the side of Christchurch Mansion is an enigmatic block of dark limestone that dates back to 14th-century Belgium.

A mysterious concrete hand reaches out from between the stones of Uniwersytecki bridge.

Two larger-than-life Sean Henry sculptures blend in with the people of Colchester's high street.

The accidental discovery of this gilt bronze head led archaeologists to find the Roman Baths in the city of Bath

A grumpy old water goblin guarding an old mill on the Devil’s Stream in Prague.