A tunnel with windows, so you don't miss out on the impressive views.

The fifth-longest natural arch in the world, and the longest outside China.

Giant pinnacles in the sun-scorched lands of Southern Utah have been nicknamed "white ghosts."

Come for the speed, leave in love with the desert.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

A commemoration of over 150 of St. Louis's favorite sons and daughters.

Giant works of art interspersed throughout meadows and woodlands offer a new discovery at every turn.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

This installation turns abstract economics into a stark, public spectacle.

What happens here stays here – unless it affects the whole world.

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

The last living thing to come out of the rubble after 9/11 is now a symbol of hope and resilience.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Once the tallest building in the world and the site of “the highest dinner ever held in New York” this building now holds the most expensive penthouse in the city.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Elevated freight railway turned wildly successful urban park.

What was meant to be a temporary exhibit is now a permanent fixture at the St. Louis Zoo filled with beautiful birds.

A chessmaster's dream destination.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.