One of Madrid's oldest trees, with a long and colorful history, resides in El Retiro Park.

Madrid's last horchata kiosk is a blue-and-white beacon of refreshment.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

A uniquely lettered street sign marks the corner where the iconic word game was invented.

Abandoned power station once home to a squatter community, now being developed into an arts center.

This enormous photomural pays homage to Vancouver's infamous history of public activism.

Two graffiti towers stand like ghosts of Vancouver's World War II-era defensive outpost.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

Oriental bazaar in the heart of Sarajevo.

This historic cemetery was inaccessible for several years due to dozens of land mines.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

A war-torn Olympic relic is being overtaken by graffiti and nature.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

This now abandoned restaurant provides some of the most amazing views of Lisboa.

This colorful and quirky set of pegasus sculptures celebrate the works of poet Zbigniew Herbert.

A hidden art gallery in an abandoned Warsaw fort.

The original resting place of Queen Cleopatra and Mark Antony's only daughter.

An extraordinary mix of Phoenician, Roman, early Christian, and Byzantine ruins beautifully set overlooking the Mediterranean.

An early Portuguese serial killer's head is alarmingly well preserved in a jar at the University of Lisbon.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.