Geothermal waterfalls in Tuscany.

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

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

This Italian stadium makes liberal use of fascist statuary to evoke classical sporting arenas.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

The Pope’s secret escape route.

If you want to talk to the Pope you will have to stare down this surreal vision of Jesus rising from a nuclear hell.

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

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

2300-year-old Roman road connecting the empire.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

Oriental bazaar in the heart of Sarajevo.

Structure built from the skulls of vanquished foes.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

Sealing couples' love since just after World War I.

In the hinterlands of Serbia's capital, a giant reflective mushroom houses an aeronautical history of the former Yugoslav republic.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

A Serbian church lit by chandeliers made of weapons.

A misnamed well, with a deep dark past.