Three columns of volcanic rock shoot out of the ocean.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

This elegant arc of a waterfall marks a religious turning point.

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

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

This fantastical waterfall is hidden in a cave located in a cracked cliff.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

The ruins of a medieval monastery named after a type of tree.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

Certain traditions prevail on the least-visited island of the Aran Islands.

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

An ancient neolithic tomb that only sees the sun twice a year.

An unusual manor of stunning beauty, born out of a crippling disease.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This abandoned Slovenian military barracks has become a punky-political art squat.

A whimsical bridge adorned with decorative dragons.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

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.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.