A tree grown from astronaut seeds which were exposed to cosmic rays.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

Golden Gate Park's historic collection of plants.

The legendary statue-hating superintendent of Golden Gate Park is honored with... a statue.

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

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

Olfactory delights in San Francisco's Botanical Gardens.

This revered mutant tree was felled in an act of ecoterrorism leaving a legacy of myth and possibly murder.

Acres of natural wonders left behind by a socialite-turned-gardener.

The ruins of the castle that chemicals built.

The home of one of California's most important horticulturalists wilts amidst a lovely park.

A monument to the love people have for their pets.

Outdoor art exhibition made of classic Tetris pieces.

Long before guestbooks and hotels, frontier travelers signed their names on this rock face.

A century-old cabin off of Highway 30 touts an unusual construction material: dinosaur bones.

Small museum packed with artifacts recovered by the man rumored to be the real-life inspiration for Indiana Jones.

Twenty-year effort to raise a castle using tools and techniques from the 13th century is now abandoned in the Arkansas woods.

A miraculous natural phenomenon known as "the spring that breathes."

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

The fossilized remains of ancient California redwoods.

This historic California cemetery holds the bodies of veterans of both the Civil War and the Donner Party.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

California's oldest wind harp represents a historic piece of America's Danish history.

Honoring the famed folktale author, this California museum looks like it belongs in the Black Forest.