The massive machine creates cracking displays of indoor lightning.

Canyon walls shrouded in ferns.

Humboldt's human-powered sculptures race across land and sea for days on end in a wacky quest for dominance.

Caves that can't seem to quit producing the remains of prehistoric humans.

Home to some of the oldest hominid fossils ever found.

A water pumping station disguised as a residential home to assuage concerned neighbors now tricks most passersby.

The decaying adobe remains of an old homestead are just off the beaten path in Joshua Tree National Park.

This train station inspired the name of a 1970's rock band and provided the backdrop for their album cover.

Hear, smell, see, taste, and touch history at this immersive Civil War hospital.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

These unusual rooms on wheels are holdovers from the 1960s.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

One of the largest helium balloons in the U.S. is a 112-foot ginormous orange.

Folk art crafted from discarded vegetable crates.

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

A vaudeville performer mounted this hollowed-out redwood log onto the chassis of a truck, and toured the country spreading a message of conservation.

This quirky UFO-shaped curiosity is often mistaken for the airport’s control tower.

More than 700 species live within this murky marvel of a swamp on California's coast.

Two rocks in a perpetual kiss and one of "the most romantic spot in America."

The oldest lighthouse on America's west coast no longer needs keepers, yet they maintain the site anyhow.

This cabin from the 1850s is one of the first structures built by Chinese immigrants in California.

Offering commanding views of the California coastline, this restaurant was a hub for the artists and bohemians of Big Sur.

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

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