A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

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

Apartment complexes built into huge repurposed natural gas tanks.

Op-art architecture designed for happiness.

The solemn exterior conceals an opulent interior of this 17th century church.

Baroque celebration of the end of the Great Plague of Vienna.

Legends surround an ancient tree trunk riddled with nails for good luck.

Designed as a reminder of one of the darkest moments in Austrian history.

Dine amidst exotic plants at this former royal greenhouse.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

Vienna's diversity-themed traffic lights were inspired by the Eurovision Song Contest.

Visiting this café is like visiting the Austrian grandma you wish you had.

Constantly maintained, this organ is playing a six-century long composition by John Cage.

This enchanting mountain plateau celebrates spooky local folklore.

This baroque palace displays an impressive collection of taxidermy, art, and rare objects from the days of courtly hunting.

A former Nazi lookout tower with a magnificent view of the Rhineland.

Crop circles inspired this whimsical garden in Germany.

A German apartment building hosting as many trees as human occupants.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A beautiful maze marks where three countries meet.