Concrete strongholds stand guard over the Golden Gate.

Marta Becket's hand-painted theater in the desert.

Centuries of crashing waves carved out this small hole in the rock, which lights up at certain parts of the year.

A masterpiece in Golden Gate Park by virtue of the artist’s debt.

A watering hole where the options for seating include a bar, patio, or subterranean cave.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

The California capital city once stood 10 feet lower than it does today.

Thousands of migrating monarchs overwinter clustered amongst the eucalyptus trees.

Millions of years of oxidation make a drive down this winding Death Valley road surprisingly colorful.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

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

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

The rocks in this arid basin leave trails of movement behind them.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

A stone pillar marking the location of the westernmost battle of the American Civil War only honors one side of the conflict.

Stairs often replace streets on the steep slopes of this old mining town.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

An incredible airplane graveyard sits outside this small museum dedicated to preserving aviation history.

See massive fossils that are over 200 million years old in northeastern Arizona.

The site of the gruesome massacre—and maybe cannibalism—of five men, a tragedy that made Alferd Packer infamous.

See 150 million-year-old dinosaur tracks and bones dating back to the Jurassic period.

A dangerous narrow-gauge railroad once traced a route through this striking canyon.