The longest navigable underground river in the United States is home to countless blind and albino animals.

An essential stop before plundering, BYO Cutlass.

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

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

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

These eerie outliers of the lightning bug family glow a mysterious blue color.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

Panorama exhibition hall in old silent theater with a beautiful backyard garden.

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

An acoustic anomaly with a mysterious cause.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

This naturally-sourced hot spring is now home to a clothing-optional resort.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

This frequently-photographed waterfall takes only a short hike to visit.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

A prohibition-style speakeasy takes up residence in the last Victorian residence in Hollywood.

A beautiful geyser under environmental threat.

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

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.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.