Structure built from the skulls of vanquished foes.

A Red Cross memorial museum at the site of the Niš concentration camp that operated for four eventful years during World War II.

An ornate plague column – built to celebrate life – claimed the lives of numerous artisans during its construction.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

Turntable anonymously received orphans, alms, and groceries.

A former Latvian headquarters of the brutal KGB secret police is now open as a grim reminder of their atrocities.

Flamboyant architecture from the turn of 20th century.

Medical museum that houses most notably the taxidermied remains of Vladimir Demikhov's famous two-headed dog experiment.

A black cat protests the City Guild in Riga's Old Town.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

The design of this beautifully crafted building was inspired by Norwegian glaciers.

A French library that makes sure its love of books is writ large... giant in fact.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

Crumbling necropolis set high above Fez.

Traditional 11th-century outdoor tannery.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The other side is actually green.

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

A hands-off space for graffiti artists to hone and display their skills.

The broken skateboards that became a poignant memorial to a murdered skater.

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

The signs of a long buried road can still be found hidden beneath a London sewer grate.