These ominous lava formations were said to be an entrance to the netherworld so of course they inspired a famous metal band.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

The Bloemen Route, or “Flower Route”, stretches 25 miles through prime Dutch tulip country as a result of “tulip mania,” the world’s first economic bubble.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

A striking 500-year-old mansion provides an unexpectedly sublime home for live deer and a menagerie of exotic stuffed animals.

The oldest inn in England served brew to the crusaders.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Twisted buildings adorn the banks of the Rhine river.

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

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

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

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

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Cold war icon and onetime "hole" in the iron curtain.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A fascinating insight into daily life in the Eastern Bloc.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Iceland's largest geothermal mud pool is a little bit haunted and a little bit dangerous.

Walk in the footsteps of the gods and straddle two tectonic plates.

Iceland's largest lagoon is home to stunning multi-colored icebergs.