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

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

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

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

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

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

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

One of the best examples of Modernist religious architecture in Mexico City.

The last home designed in its entirety by noted architect Luis Barragán owes its existence to an impressive jacaranda tree.

This giant expressionist head crowns a museum devoted to a beloved Mexican leader.

The museum houses "the most studied meteorite in history," among other geological oddities.

Murals made with millions of colorful stones adorn the abandoned building.

This colossal ancient jaguar sculpture was used as a vessel for the hearts torn from sacrificial victims.

The ruins of the "place of the cloud snake" sit in the middle of an urban environment.

Underneath the historic center of Mexico City, the remains of a temple dedicated to the Aztec god of the wind.

This colossal ancient sculpture of the monstrous Aztec rain god has a literally stormy history.

This foreboding building was the headquarters of the terrifying Spanish Inquisition in Mexico.

This extraordinary art museum is like a secret world on the edge of Mexico City.

The burial place of some of Mexico's most prominent residents is full of macabre stories and hidden masonic symbols.

Located in a veterinary school, this macabre exhibit displays the effects of animal diseases.

This French cemetery houses some of the most exquisite examples of funerary art in Mexico City.

A small pack of an ancient, hairless breed of dog once believed to guide souls through the underworld lives on its grounds.

Abandoned figurines adorn a small plot on the side of a craft market's entrance.