This geothermal hot spring hides beneath a slowly growing mineral dome.

Canyon walls shrouded in ferns.

Here, at the "world's longest art gallery," you'll find forty miles of ancient petroglyphs and pictographs.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

Carved by a waterfall in a hard-to-reach rock formation, this heart-shaped rock has inspired romantics for decades.

A hand-built folk art installation covered with messages of God's love.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

A walk through the historic city center, under the streets of Seattle.

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

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

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

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

A psychedelic labyrinth on the San Francisco bay.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

The remains of a 12th-century chapter house in Golden Gate Park.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

This partially buried wreck is one of the most complete of its kind but is only revealed when the sea allows.

The rusting remains of the largest assembled WWII fleet on the West Coast.

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.

A 300-ship graveyard, with a few still visible at low tide.

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.