A hidden subterranean installation offers a view of the sky.

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

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

In this century-old literary safehouse, print is alive and well.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

Visible below the waves are memorials to the city's Gold Rush dead.

A modern mechanical planetary system, part of a 10,000 year clock.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

Tiki luxury on Nob Hill.

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

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

Olfactory delights in San Francisco's Botanical Gardens.

A museum befitting the city responsible for supplying the majority of the world's LSD.

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

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

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

A 140-year-old castle with underground caves hidden in San Francisco.

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

South Carolina's last remaining slavery auction house is now a museum devoted to its own tragic history.

A hobby born from insomnia has turned into a hangar full of objects that have been be-buttoned by the Button King.

The sole remaining outpost of a once-thriving South Carolina chain still sells “pic-a-nic” baskets.

This abandoned lighthouse looks like a rusting oil rig, but has managed to survive a number of storms.

A curious collection of oddities including a lock of Alexander Hamilton's hair and Harry Houdini's ouija board.

A mailbox that saved a nature reserve.