What was once the largest NFL stadium.

A painted-over wall in Detroit originally built to segregate a black community from an adjacent white development.

Weighing 30,000 pounds, this monument represents Detroit's first industrial era.

The bones of an old zoo crumbling in the shadow of a new one.

Advice-columnist's bell tower, paid for with pennies.

More than 450 years ago, an Italian nun became the first woman to paint the iconic subject.

Secret refuge and museum of the Duke of Florence.

The mummified relic of St. Antoninus.

A plaque on the base of this statue holds a bewitching design.

Two planes stand abandoned after the closure of an aircraft-themed restaurant.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

The graveyard is filled with beautiful funerary art and boasts breathtaking views of Florence.

The people of Padua pledged to construct this church if the city was spared from destruction during World War I.

The oldest botanical garden in the world that technically isn't the oldest.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

Something's missing between the arcades of the Palazzo della Ragione in "the city of the three withouts."

This old medieval prison tower has been a site of astronomical research for more than 250 years.

The secret medieval communication system will whisk your words above the noise of the crowd.

Third time's a charm, or in this case, two testicles are.

A brutalist gem towering over the heart of Milan.

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

A small sculpture that pays homage to the famous bronze ear of Ca de l'Oreggia—or does it?

Just across from the "Last Supper" painting is the famous painter's vineyard, a gift received for creating the masterpiece.

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