Only gap in the 30,000-mile span of roads called the Pan-American Highway.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

A historic dam made famous for its turbines and feature in a Hollywood classic.

One of the world's largest automobile junkyards is a unique landscape of metal and moss.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

A recreation of the doomed ocean liner in the middle of the Smoky Mountains.

Enormous lake at the bottom of a unique cave system.

A bronze sculpture honors the 12 black students who attended the first integrated public high school in the segregated South.

A psychedelic labyrinth on the San Francisco bay.

Europe's largest natural bridge has a 19th century royal chateau built into its side.

The legendary cliffside castle of three-time Voivode of Wallachia, Vlad the Impaler.

This snug medieval lane is one of the narrowest streets in the world.

On a small Slovenian island, diners can mix and match a classic cake into dozens of sweet and savory flavor combinations.

These 12th-century catacombs carved into a mountainside were a place of mysticism and Christian hermitages.

This is the oldest Roman-made bridge in the city still existing in its original state.

This basilica is dedicated to two saints, one of which is known more for his famous quote.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

A forgotten "city of water" underneath the famous Trevi district.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

Dedicated to the "father of modern education," this museum documents the history of education in Czechia.

This doorless 20th-century elevator doesn't stop or slow down.