The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

From pre-war whiskey cocktails to prohibition-era speakeasy secrecy, this bar has seen it all.

One of the last free public hot springs is decorated with hippie art.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

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

Her final resting place was intended to be modest and private, but the power of her popularity continues to draw visitors.

The abandoned personal amusement park of the King of Pop.

This massive redwood tree has a hole in the base big enough to drive through.

Travelers exchange letters with woodland creatures at this mini post office.

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

The final resting place of a space program monolith.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

The programmatic glory of LA's giant whiskey barrel building has become an upscale reminder of the city's kitschy roadside past.

A ghost town at the airport is now a refuge for blue butterflies.

This Big Sur waterfall drops 80 feet directly into the Pacific Ocean, and inspired the hillside house up top.

Eons old volcanic activity created one of the most stunning rock formations in the United States.

Stripes of flowers bloom each spring in a 50 acre rainbow of color.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

Canyon walls shrouded in ferns.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

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

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

Carved by a waterfall in a hard-to-reach rock formation, this heart-shaped rock has inspired romantics for decades.