San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

With the touch of a button, you can read a randomly selected short story.

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

A Manhattan courthouse hides a small but scathing memorial to Holocaust injustice.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

Exotic feline breeding compound and conservation center.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

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

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

A strange house built only at night, with rumored mystic inspiration.

This former stomping grounds of the most eminent astronomers of the early 20th century.

Where the first "expert riders, willing to risk death daily" for the Pony Express were recruited.

Rifle through images of skyscrapers, Worlds Fairs, and more in the largest public postcard repository in America.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

A psychedelic labyrinth on the San Francisco bay.

The remains of a ruined mansion memorialize the 1906 earthquake.

An eccentric home stands out in an otherwise average neighborhood with mosaics, mini topiaries, and kinetic sculpture.

One of Savannah's oldest and most haunted cemeteries, featuring graves desecrated by Sherman's Union Army.