Walk through Czech history in Prague's largest graveyard.

The largest cave chamber in Britain—big enough to fit a whole cathedral inside.

A museum in the childhood house of a medical pioneer.

An early Portuguese serial killer's head is alarmingly well preserved in a jar at the University of Lisbon.

An eerie, derelict amusement park in Berlin.

The abandoned remains of this Victorian brewery hide crumbling bowling alleys and rusting industrial gear.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

The world's only museum devoted to the wonders of fluorescence.

A floating cat sanctuary on an Amsterdam canal.

Hidden within a Netherlands crater is a stone bed that lets those who lie in it see the sky as a curved surface.

If your school was decorated with trippy graffiti, served ambrosial coffee, and was frequented by mimes, it might have been similar to this groovy cafe.

This narrow path was cut right into a French mountainside to feed the country's early naval expansion.

15,000 year old bison sculptures.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

Famed architect Antoni Gaudi built this generous thank you gift to a friendly host who housed him during a job.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Wonderland replication in progress by one persistent man.

A network of concealed passageways lies within a busy London Underground station.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.