Longest fortress system anywhere in Europe.

An ancient knight and a symbol of the city's freedom.

Monasteries on rock pillars, once accessible only by frayed ropes.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

An ancient capital city that dates back 3,000 years and harbors many surprises.

A "miracle" that seems to produce more holy fistfights than holy revelations.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Op-art architecture designed for happiness.

An underground city of salt.

Naturally formed rock city in Poland.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

The largest toy museum in Poland showcases Europe's history of childhood.

Relive a Polish uprising via an enormous, century-old cyclorama.