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

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

A crumbling Beaux Arts monument to the Bay Area's age of rail.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

Commonly referred to as the most photographed Victorian home in the United States.

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

Bonsai garden in Oakland is curated by the first non-Japanese female bonsai master in the United States.

Dyed by iron oxide over centuries, these sandstone rocks rise thousands of feet into the sky.

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

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

The liveliest ghost town in the state.

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

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

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

Home to the "Circus" trees created by Axel Erlandson.

One of the most unusual geological features, recognizable from a dozen hit movies.

A giant Troll lurks under one of Seattle's oldest bridges.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.

The ghostly remains of an accidental sea.

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

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

The rocks in this arid basin leave trails of movement behind them.

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