An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

This vast World War II defense line was the site of a fierce battle.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

This winding road through an Italian canyon may be the most scenic drive in the world.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

A unique seaside cave where Aleister Crowley faked his own death.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

This massive steel pyramid can be entered by a set of jagged steps that let visitors stand in its heart.

Apartment complexes built into huge repurposed natural gas tanks.

Vines grow up the metal bars in this public park created from an old machine factory.

This historic covered bridge contains a series of macabre paintings that communicate one thing: everyone dies.

Catacombs turned marketplace.

Scattered throughout London are ancient remnants of the city's former bounding wall.

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

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

"Respectful to the dead, safe and sanitary to the living, dedicated to the Genius of Memory..."

This stately monument has been wearing a traffic cone hat for decades much to the delight of the locals.

Displaced highlanders would take shelter from the wet Scottish climate under the large walled bridge at Glasgow Central Station.

A scattered trail of street art adds a pop of color to the city's stark structures.

It was once nicknamed "the most bombed hotel in Europe."

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.