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

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

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

Concrete strongholds stand guard over the Golden Gate.

In one of the hottest parts of the Mojave Desert, shallow bedrock forces the typically dry Mojave River to the surface in this canyon, providing a vital oasis for humans and wildlife.

This giant temperature attraction created some giant electric bills.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

The abandoned train depot now doubles as a well-placed rest stop for those who take the road less traveled.

The largest dune field in the Mojave offers a chance of hearing the 'singing sands.'

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

A sculpture of the famous photograph stands on San Diego's "Greatest Generation Walk."

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.

A natural dome made of volcanic glass in Inyo National Forest.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

The echoes of a railroad town that solemnly mark the end of the line.

A charming desert roadside bakery that produces 10 times more bread daily than it has residents in its town.

This rock formation named for its unique shape is one of many that call the Alabama Hills home.

Smooth basaltic rocks tell a tale of ancient glacial waterfalls.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

Fourteen curious and controversial white bunnies sit in a circle near Newport Beach City Hall.

Oldest building in California still in use.

Rich red almandine gemstones are waiting inside the volcanic rock strewn across this eastern Nevada hillside.