The world's oldest rose is so tough it survived being bombed in World War II.

A monument to the "father of modern warfare" Gustav II Adolf.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

One of the most iconic neon ads of former East Germany.

This small exhibition displays equipment and artifacts once belonging to the feared Stasi secret police.

This residence straddles a border between Belgium and the Netherlands.

A reconstructed World War I-era communications array that was once hidden in plain sight.

A maze of crosses marks the jumbled divide between the Netherlands and Belgium.

A tribute to smugglers and the Butter Wars.

Scale model of St. Peter's Cathedral (Rome) in the middle of a small Dutch town.

Stained-glass windows inspired by Vincent van Gogh's paintings decorate this church in the town where the artist's career began.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

A subterranean shelter remains intact under a busy Paris railway station.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.