An extraordinary "City of Caves" carved from solid stone.

The world's oldest bookshop still in operation.

Entire apothecaries are on display at this Lisbon museum, which explores the history of medicine.

Spain's largest bullring offers a unique glimpse at architecture and history.

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

The word 'wunderkammer' translates as 'wonder-chamber'. This Wunderkammer is both a museum and a retail store.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

An opal mining town in the middle of Australia where people live, worship, and shop underground.

This experimental utopian "city of the future" in rural India may hold a dark secret.

Once an indicator of social class, the color blue has come to define this city on the edge of the Thar Desert.

The 953 windows undoubtedly make this the world's most beautiful screened porch.