A playground inspired by differential calculus dangles from the ceiling of the Liberty Science Center.

Now abandoned, the first public health hospital in the U.S. saw more than one million immigrants from around the world.

World War II bunker still standing on the New Jersey beach.

A bronze monument to the infamous radio broadcast in the real New Jersey town where the fictional Martians crash-landed.

A recently abandoned psych ward at the end of Sanatorium Road.

This Great Depression-era creation was once known as the strangest house in the world.

A reservoir of vintage pinball machines and arcade games for the nostalgic and thrill seeking.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

This Seattle museum displays the history of the telephone through an impressive collection of telecom equipment.

This semi-secret garden in south Seattle emulates a traditional Japanese garden using the plants of the Pacific Northwest.

Couple's personal collection of pinball machines turned public pinball museum.

Make your reservation to have coffee with some kitties.

A house filled to the brim with oddities and curiosities.

Seattle's own bad art museum located inside Cafe Racer.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

A 100-year-old purveyor of curiosities, curios, and kitsch featuring mummies, shrunken heads, and a Fiji Mermaid.

A former hardware store near Yerba Buena is the official home of California's history.

This print shop boasts one of the largest pinball arcades in San Francisco.

San Francisco’s condensed garden of incredible plant growth.

A century and a half of research in the sciences and natural history, still going strong.

The sole surviving relic of the San Francisco neighborhood cobbled together from old horsecars and streetcars.