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

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

An underground magnet for ever-changing street art.

Scattered around Atlanta are little doors with big charm.

This titanic oil company sign is a reminder of the Americana boom of the 1970s and also its commoditization.

A chessmaster's dream destination.

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

Less a museum than a bizarre fantasy world created by artists and engineers.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

This Transylvanian church has changed its denomination four times.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

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

This massive underground salt mine now holds a sci-fi theme park in its depths.