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

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

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

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

Once the home of a hermetic monk, this cave now houses a small church.

A preserved college lock-up that recalls a clubhouse approach to discipline.

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

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

The most visited, and possibly most controversial, museum in Germany.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

A unique underground structure dating back to the 1st century BC.

This ancient theater was once the home of fierce gladiatorial battles.

Dedicated to the outnumbered Finnish forces who pushed back Soviet forces during the conflict.

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

Rubbing the buttons along this statue's coat is considered good luck.

Estonia's largest creative city is a vibrant bohemian hub located within a former industrial complex.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Copenhagen's celebrated theme park and gardens.

Old Danish castle immortalized in Shakespeare's Hamlet.