The largest self-built castle in the U.S., six decades in the making.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

This fully intact Neoclassical-Greek Revival style firehouse operated until 1938.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

The southernmost outpost of the Russian Empire in colonial America.

North America's largest accredited model railroad museum.

L. Frank Baum wrote part of the "Wizard of Oz" series in this wooden Victorian beach resort.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

California's own majestic geyser is powered by a subterranean volcano.

The haunting ruins of Jack London's dream house.

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

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

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

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

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The longest non-mortared wall in the country is one man's tribute to his displaced Yuchi ancestor's five-year journey to her homeland.

Although now a decaying ruin, this stone cabin's history includes several notable figures.

Arizona's first government hub is a rustic cabin now preserved as part of a historical museum.

This huge dam across the Colorado River caused an armed standoff between two U.S. states.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

A spiritual vortex among the red rocks in Sedona.