A former plague hospital turned medical museum.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

One of the Leiden's oldest pubs is also the birthplace of the Heineken star.

A market built atop boats is one of the few floating holiday markets in Europe.

The remains of a medieval wall discovered in the basement of a jewelry store.

A trio of red, white, and blue stones embedded in the streets of Leiden are markers of medieval territory and law.

A plaque hidden in the law faculty at Leiden University honors the first scientist to make liquid helium.

Graffiti covers the walls of a room where university students through the centuries have waited nervously to defend their theses.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

A miniature city, once ruled by the Queen of the Netherlands.