Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

One of Europe's largest supercomputers is housed inside of a disused chapel.

A once-secret library of Freemason history in Catalonia.

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

This hidden museum examines the complex history of the country's law enforcement.

The last Victorian market in Belfast.

This Victorian-era public house has set the standard for pub-style elegance for over a hundred years.

Did he come up with a theory of cosmic-ray showers while sitting in this bath?

The final resting place of one of the brightest physicists of the 20th century.

Once a meeting point for great thinkers, and the midpoint of the country.

An old Danish political institution where members of government can grab a drink off the record.

Visitors are treated to a stained glass kaleidoscope interior inside this work of art.

Museum on earth sciences featuring a recreation of a famous curiosity cabinet.

A novel collection of medical curiosities housed in an 18th-century surgeon training academy.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

A little-known cafe in an old copper bridge tower with 360-degree views of the harbor.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

This sublime architectural marvel is a rare example of an expressionist church.

Art and armour fill every inch of this rich kid's Italian villa.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

The largest and most famous wax anatomical collection anywhere in the world.

Thousands of miniature bronze sculptures have taken over this city square creating a unique art installation.

This abandoned office building is a lasting example of Soviet-era architecture.