This fifth-century church is one of the oldest Christian sites in the Balkans.

Step inside this medieval Orthodox gem and travel back to the 16th century.

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Romania's only crater lake with water as pure as if distilled.

Conspiracy theories and occult legends surround this mysterious natural rock formation.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Hamburgers are intensely proud of their tunnel beneath the river.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

Eat the ultimate iteration of Portugal's most beloved pastry.

The notorious "Hanoi Hilton" where Vietnamese colonial subjects and later American POWs, including John McCain, were imprisoned.

An extravagant monument to an extravagantly unpopular Emperor.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

Eighty million natural history specimens call this gargantuan museum home.

This charming pup is meant to celebrate the youth and stubbornness of the city's students.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

One of the most controversial statues in Romania is an emperor with no clothes.

This sculpture used famed boxer Joe Louis as the inspiration behind its body.

This metro station doubles as an unintentional paleontology museum.

The kitsch mansion of the former Romanian president Nicolae Ceaușescu features a golden bathroom.

The bust of Romania’s most notorious ruler, Vlad Dracula aka "Vlad the Impaler," keeps watch over the ruins of his medieval court.

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