A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

The surviving remnants of a destroyed medieval church now stand in a public park.

This Gothic church houses ornate royal tombs and a magnificent gilded altarpiece.

This whimsical winery by Antoni Gaudí looks ripped from the pages of a fairytale.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

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

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This museum was invented in a novel before being made real by the author.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

Standing proud atop a Turkish bluff, this Ottoman palace has retained its grandeur despite being abandoned for centuries.

A fountain standing as a testament to a doomed alliance.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

This church houses the tomb—but not the remains—of St. Nicholas, the likely progenitor to Santa Claus.

This historic hotel preserves many treasures from its heyday hosting passengers on the Orient Express.

This column celebrates Rome's victory over the Goths, and may be the oldest Roman monument in Istanbul.

Ottoman-era houses lovingly preserved.

The ornate miniature mansions were built for Istanbul's feathered residents.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

The ancient abodes are a testament to human ingenuity amid harsh climates.

Climb a set of vertiginous stone steps to the top of this impressive ancient edifice.

A Turkish monastery tucked into a cliff wall.