This massive concrete sculpture is said to be the heaviest communist monument on Earth.

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

Historic medieval fortified city in southwest France.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Abandoned Nazi train station turned underground astroparticle laboratory.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A Neolithic burial site built 1,000 years before Stonehenge.

England's most notorious suicide spot.

A church that bred legends, and served as an inspiration for the Da Vinci Code.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.

Thanks to both terrific preservation and historic vandalism this ancient site is known as the "Heart of Neolithic Orkney."

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

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.

Bridge that died in war and was resurected.

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

An underground city of salt.

This abandoned Olympic skiing facility still bears the scars of the Siege of Sarajevo.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

This snug medieval lane is one of the narrowest streets in the world.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

This brutalist monument is inscribed with 9921 names of Yugoslav partisans who perished during WWII.