This Polish cave has housed a dragon, a brothel, and an enduring legend.

An underground city of salt.

Museum in a swimming pool where the water still flows.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

A mocking tribute to the past and modern leadership of Prague.

Macabre astrological automaton clock dating to the late 1400s.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.