The silly symbol for an underground protest group is now scattered around the city.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

Museum dedicated to "the man who moved the Earth."

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This man-made mound monument was built out of soil from all across the Polish empire.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

An underground city of salt.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

A peculiar clock commemorates a historic victory won by ringing the noonday bell an hour early.

Looming communist pillar with a Czech twist.

Europe's largest natural bridge has a 19th century royal chateau built into its side.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

A marvel of Byzantine engineering under the streets of Istanbul.

The ruins of an early-18th-century complex that could once house up to 12,000 horses.

Morocco’s modern capital was once a haven for Barbary pirates, who went so far as to establish a republic of their own.

Designed as a labyrinth, this subterranean prison was crafted without bars or doors.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

This former royal palace with gorgeous gardens became the first museum in Morocco.

Traditional 11th-century outdoor tannery.