The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

Odd outsider art installations surround a Gold Rush-era ghost town.

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

Only known mainland rookery of the threatened Stellar sea lion.

Home of Howard Hughes' Spruce Goose.

Hollowed out cedar log tubs set in an ancient towering forest.