Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This building has survived for more than a century and remains virtually untouched.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.

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

This ducal residence was once home to a future Russian empress and a French king in exile.

This ornate church has survived Nazi and Soviet occupation, including a short stint as a Soviet-era gymnasium and cinema.

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

The reconstruction of this prominent building fulfilled a long-written command.

These abandoned vessels are destined to be reclaimed by the forest.

Flamboyant architecture from the turn of 20th century.

The oldest housing complex in Riga is a mini timeline of architectural trends.

Also known as Uncle Karl, the beloved bronze copper keeps a watchful eye on St. Stephen’s Basilica while people rub his lucky belly.

The only natural cave bath in all of Europe.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

The massive white mound and accompanying water terraces are a striking geological oddity.

An industrial site turned into Hungary's most cherished natural wonder.

A collection of intricate sculptures so small they have to be seen through a microscope.

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

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

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.

Launched by Napoleon's soldiers more than 200 years ago, a cannonball remains embedded in the tower wall.