A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

A lush green oasis in the middle of Chicago.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

A beautiful geyser under environmental threat.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

A 6-mile-long lake created by an apocalyptic seismic event and the deadly chain reaction that ensued.

The residents at this Yellowstone wildlife park will certify your cooler as "bear-proof."

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

This raised bulls-eye visible from space was the subject of an intense geologic controversy.

A sharp bend in a dramatic river canyon cut through red rocks.

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

The second-largest gold nugget in existence, displayed in a Las Vegas casino conveniently named the Golden Nugget.

An exotic wildlife habitat right off The Strip.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

A mechanical clock built in 1914, with a rotation of 12 historical figures on its face.

Designed as a reminder of one of the darkest moments in Austrian history.

The Habsburgs' royal collections of art and wonders.

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.