Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

This unique religious structure is an architectural gem with arresting ocean views.

The fire inside this temple has burned for more than 1,500 years.

Metro station with a claim to rock n' roll fame.

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

Where once there was a train station bathroom, there is now this German burger joint.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

An eerie, derelict amusement park in Berlin.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

Looming communist pillar with a Czech twist.

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

Macabre astrological automaton clock dating to the late 1400s.

A peculiar clock commemorates a historic victory won by ringing the noonday bell an hour early.

Europe's second largest ossuary wasn't discovered until 2001.

Op-art architecture designed for happiness.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

A relic from the Industrial Revolution got a second life as a contemporary performing arts space.

A whimsical bridge adorned with decorative dragons.

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

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.