An 1814 castle that hosts an exhibit of "explorabilia".

The bartenders at this crime-fighting theme cafe are actual private detectives by day.

This restored 17th century synagogue is one of the few remaining structures in Morocco’s ruined Jewish quarters.

The oldest known university in the world is in Fez, Morocco.

Traditional 11th-century outdoor tannery.

This former royal palace with gorgeous gardens became the first museum in Morocco.

This embalmed man is one of the best preserved mummies from the Canary Islands.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

Built to house a chapter of the Knights Templar, this grandiose building is a relic of Freemasonry in Chicago a century ago.

A little-known subterranean street runs under some of the best-known buildings in Chicago's River North.