The longest burning light bulb in the world.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

Handmade treasures from around the world.

Julia Morgan's Moorish-Gothic labyrinth of fountains, trees, natural light and Oakland's notable dead.

A large instrument played by the wind.

An "anarchical" no man's land, complete with garbage sculptures and a hobo-run "Landfillian Library."

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

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

An artsy hidden staircase leads to breathtaking views of San Francisco.

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

A free, public museum dedicated to the fascinating science of sight.

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

A modern mechanical planetary system, part of a 10,000 year clock.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

A huge musical instrument played by the ocean.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

Tiki luxury on Nob Hill.

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

The only theatre in the world constructed specifically for sound movement.

A stunning, abandoned limestone quarry in southern Indiana provided the stone to erect the Empire State Building.

A modern-day wunderkammer dedicated to Indianapolis history, Afrofuturism, and musical vibrations.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

The scuba diving training facility was named for the steam that rises from the cave's chimney.