This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

2300-year-old Roman road connecting the empire.

France's most famous cemetery, with some of its most curious tombs.

Notorious artist squat renovated into legal studios.

This hidden art nouveau gem was designed by an architect in search of a national style.

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

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

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

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

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

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

A restaurant and observation deck built in a unique broadcasting antenna.

Berlin's old airport.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

An eerie, derelict amusement park in Berlin.

Established in 1638 to battle the Black Death, this botanical garden is a treasure trove of rare flora.

A beautifully eclectic mix of architectural styles.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

Former estate of Lenin, now home to his death mask.