At one of Berlin’s oldest churches, visitors can place mosaic tiles to help restore a medieval mural.

A series of playful yellow penguins share a serious message about the environment.

Countless grotesque faces stare out from this eerie Prague art wall.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

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

One of the famous Czech artist's lesser-known Prague installations appears to be a glowing fetus affixed to a drainpipe.

This spooky statue sits outside a famous Prague theater.

Some of the greatest minds in the history of Hungarian art and science converged in this café.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

An alchemist's “magic door” stands in the middle of a Roman park.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

This statue is the only female representation of Rome's "talking statues."

A self-funded cemetery with a long list of inhabitants.

A special train service transported Sydney's dead from this station to "Necropolis Receiving Houses" at Rookwood Cemetery.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A statue representing a lost Roman profession that was vandalized for centuries.

This ancient market is often referred to as the oldest shopping mall in the world.

A sculpture serving as an homage to Pope John Paul II.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.