Inside this Krakow church, an explosion of psychedelic color.

A New York–based physician returned home to Spain to build his own elaborate monument to Christopher Columbus.

This surreal-looking tree pruned more than 1,000 years ago is still producing olives for oil.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Legends surround an ancient tree trunk riddled with nails for good luck.

Nestled in the heart of Milan is a real wunderkammer of morbid curiosities.

This Dutch art piece became a Russian icon.

Small on the outside, big on the inside, this church is an astonishing act of visual deception.

Invented in the mid-19th century, this machine could send copied images via telegraph lines.

The mark of the Devil's horns on a marble column in Milan.

The train platform where Jews were sent to concentration camps is now preserved as a Holocaust memorial.

One of the world’s smallest bars, just 13 square feet, is brimming with speakeasy flair.

This grisly effigy displays an early Christian martyr who was skinned alive and beheaded.

Da Vinci's equestrian statue, 500 years in the making.

The odd depiction of the Virgin Mary and baby Jesus is rooted in the Catholic Church's eradication of Catharism.

"The prettiest love letters in the world" ... or so said Lord Byron.

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

This giant middle finger statue sends an unambiguous message to Italy's bankers.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

A 2,000-year-old wine press hidden in an overlooked park in Tel Aviv.

Tel Aviv's popular neighborhood went though endless waves of transformation.

A "miracle" that seems to produce more holy fistfights than holy revelations.

Hidden out of public view in the National Library of Israel is a collection of "Stalag's," 1960s Nazi themed porno paperbacks written and consumed by Israelis.

This family tattoo parlor has been inking religious pilgrims in the Middle East for 700 years.