Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

This basilica is dedicated to two saints, one of which is known more for his famous quote.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

The world's most elegant power lines.

Moorish signal station on a stratgic rocky outcrop.

A Spanish town built into the cliffs.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This massive blockhead sculpture hides an entire library.

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

A fake Transylvanian castle houses a cathedral of antlers.

Museum dedicated to the terror regimes of Hungary.

This easily overlooked memorial immortalizes the scars from the 1956 Hungarian Revolution.

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

Eastern Bloc nostalgia, anybody?

A striking symbol of the Bulgarian capital.

This building has two facades of clashing architectural designs.

Sofia's legislative center is continuously reinventing itself.

"Holy Wisdom" overlooks the city that became its namesake.

The silly symbol for an underground protest group is now scattered around the city.

A 90-ton, gravity-defiant steam locomotive shoots for the skies in this bizarrely beautiful public artwork.

Extremely famous in his native country, this Cracovian painter is all but unknown beyond Polish borders.