The vast, legendary catacombs hold secrets much stranger than stacked bones.

One of the world's tallest statues is also one of its most hated.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

Physicist’s epitaph provides final confirmation to a career of turmoil.

An ornate private entrance to the Vienna subway built specifically for the emperor.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Op-art architecture designed for happiness.

This former insane asylum now holds a pathological anatomy museum.

The final resting place for the remains of 143 Habsburg royalty.

An abstract monument to a symphonic composer.

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

The modern birthplace of Irish freedom.

Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

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

This handsomely carved wooden church is more than 800 years old.

Across the Pacific in a raft, a museum dedicated to Thor Heyerdahl's now legendary expedition.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

Swedish skyscraper with a 90° twist.

This chimerical bridge/tunnel appears to dead end right into the sea.

Old Danish castle immortalized in Shakespeare's Hamlet.

Climb to the top of its spiral spire for spectacular views of Copenhagen.