Most-visited and most-photographed slot canyon in the American Southwest.

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

Despite its name, this route in southern Utah offers a heavenly day trip.

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 mysterious "wedding cake" castle in the middle of the urban desert.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A 300-ship graveyard, with a few still visible at low tide.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A winding path built in secret on the edge of the continent.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

The final resting place of a space program monolith, soon to be unveiled again to the public.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Modern commuters still pass through this 2,000-year-old Roman archway.

Legend says this demonic carving inside a medieval cathedral was one of Satan's minions.

The oldest of the three remaining bridges in England with buildings on top of them.

An enormous steel waterfall is a nod to the substance that shaped Britain's Steel City.

The heroic tale of a remarkable pup who refused to leave her master's side, no matter what.

This chain of artificial lakes was an ideal test ground for the aircraft that would carry the "bouncing bombs" used by the WWII "Dambusters" squad.

A magnificent winding road through a steep valley, with deep natural caverns at the bottom