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

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

Tiki luxury on Nob Hill.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Quite simply the largest tree in the world (by volume).

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

The world's longest known cave system.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The magic's in the hole!

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

San Francisco's newly reopened hands-on science museum.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

One person's lost luggage is another person's treasure.

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

Olfactory delights in San Francisco's Botanical Gardens.

Each year these high desert hills are absolutely covered with poppy flowers in a surreal show of nature.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

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

Its buzzing collection honors vibrator history.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.