The largest historic preservation organization in the United States.

This library and museum is dedicated to the life and literature of the Indianapolis native author.

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

Once adorning a New York skyscraper, these reclaimed ruins now haunt an Indiana park.

A man-made island in scenic San Francisco Bay.

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.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

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

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

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

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

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A huge musical instrument played by the ocean.

Civil War soldiers, captains of industry, and paupers all interred on historic grounds.