Travelers exchange letters with woodland creatures at this mini post office.

This narrow coastline trail through the dense Kauai wilderness is among the most beautiful and dangerous in the world.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

Outsider art or homage to aliens?

This museum boasts the ninth-largest collection of insects in North America.

A goddess-topped water fountain in Chicago was created thanks to the dreams of a thirsty newsboy.

Dentist's hated concrete colossi are now beloved icons of the community.

This former boomtown "island" is now submerged below Folsom Lake.

Concrete strongholds stand guard over the Golden Gate.

A living time capsule of the 1960s Richardson Bay water-front.

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.

This "life-size" depiction of Mickey Mouse as a half-lobster is both whimsical and a bit creepy, standing guard over the Boston waterfront.

Twin Peaks' real life Double R Diner has been restored to its damn fine television look.

The ancient tomb acts as a calendar that keeps perfect time.

This abandoned boat was left in place thanks to its rotting beauty.

A Hawaiian stairway to heaven—that you can't climb.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

Submerged lava formations create incredible waterworks.

This black shoreline is made up of exploded lava particles.

A century and a half of research in the sciences and natural history, still going strong.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

Russian history in San Francisco.

The best place in the park to test out your throwing arm.

Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.