Elevated freight railway turned wildly successful urban park.

Great place to have a drink and a bite to eat in an atmosphere laden with New York's Bohemian past.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

A drawbridge named for a potentially intersex Polish national who fought alongside George Washington during the American Revolution, and an example of "Pulaski Red".

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

The second-largest (of only two in the world) large particle collider is the underdog of experimental physics.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The highest peak in the state of Vermont has some interesting features.

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

Pilgrimage site for star-crossed lovers.

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

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

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Breathtaking and huge 430 year old maps of Italy.

Erotic art covers the walls of the largest ancient pleasure palace.

The world's most active stratovolcano is almost always erupting.

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

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

Museum dedicated to the terror regimes of Hungary.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.