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

A sign at the end of the Santa Monica Pier marks the traditional end of the legendary American highway.

Quite simply the largest tree in the world (by volume).

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

San Francisco's newly reopened hands-on science museum.

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

Uninhabited islet in the Caribbean is the sanctuary of giant lizards.

This huge pile of volcanic boulders hides a stunning network of secret grottoes.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

An architect's childhood fantasy treehouse made real.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

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

The first declared National Monument in the United States.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

An authentic replica of an Asian temple and garden hidden amongst the natural beauty of Hawai'i.

Watch the newest land on the planet form before your eyes.

This black shoreline is made up of exploded lava particles.

This historic hotel on Bathhouse Row in Hot Springs National Park has a storied history of gangsters and baseball greats.

Some North Carolina Cherokee have been keeping their history alive for decades with a single play.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The uniquely-designed winter home and sculpture studio of Anna and Archer Huntington.

The museum chronicling a treasure hunter's dream, fulfilled.

A historic presidential getaway on the continental United States' southernmost island.

"We Seceded Where Others Failed."