Boise State's stadium was the first non-green football field in the world.

Supposedly Satanic numbers adorn this preserved submarine sail.

Jail from the 19th century that was built by inmates.

Home to the deepest rift anywhere on Earth.

One of the tallest bell towers in Italy plays a particular melody at just two times each day.

This Roman amphitheatre was also the location of the first gladiator school.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This medieval city gate is now a blend of the past and the modern world.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

A massive bridge forms part of an aqueduct that was deemed an architectural wonder of its time.

Italy's third-largest Roman arena gives a peek into the underground operations beneath the ancient spectacles.

The oldest volcanology research center in the world.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

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

A popular legend claims that the famous pizza was invented at a restaurant in this alley.

A tree that defies gravity grows in an ancient ruin.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

The only museum with its curator—and her pets—buried inside.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.