The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

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

One of the world’s largest collections of petroglyphs records 2,000 years of human activity.

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

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

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

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.

The unusual patterns in this rock formation result from two distinct modes of weathering.

A modern mechanical planetary system, part of a 10,000 year clock.

Once the fastest ship from San Francisco to Tahiti, the Galilee now lays in pieces in three different cities.

An unassuming grey box sitting on San Francisco's Pier 17 is a "sky diary" of the coastal city's temperamental weather.

Visible below the waves are memorials to the city's Gold Rush dead.

The only visible piece of San Francisco's most famous shipwreck.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

The largest whiskey stash on the West Coast survived the 1906 fires--but not without heroic effort.

Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

San Francisco's newly reopened hands-on science museum.

A rococo retro-futurist future-rustic vernacular between yesterday’s tomorrow and the future that never was.

A classic advertising icon immortalized in regal bronze.

Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

Art from the latest counter-culture; kids who dye their hair blue and believe the future will be a post-apocalyptic water world.