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

The original place where water met land in the City by the Bay is outlined in brass.

Private collection of art inspired by cabinets of curiosity.

The seamy, underground secrets of Portland's criminal past.

This Puget Sound military post has a long, turbulent history as a gateway to the Pacific.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

An enclosed rotunda at the Henry Art Gallery in which viewers can look up and see the uninterrupted sky.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

A colorful architectural gem in Seattle's uniquely modern Central Library.

A small Richmond island dotted with the remnants of hundreds of years of history.

Hear the tales of New York's most notorious criminals.

A museum collection honoring the long history of the FDNY is held in a disused Manhattan fire house.

The Underground Railroad passed right through this historic Brooklyn Heights church.

A plaque immortalizes the spot where the early American spy said his famous last words: "I only regret that I have but one life to lose for my country."

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

These light, hollow rolls have been linked to Acadia National Park since the 1890s.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

This meticulously extracted nervous system allegedly came from a 19th-century custodian who donated her body to science.

The state's oldest continuously operating museum houses more than 5,000 Civil War artifacts.

Pulled from the rubble of one of the worst modern tragedies, a steel crossbeam became a symbol of hope for New Yorkers.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.

Harlem park dedicated to compulsive hoarders killed by their own junk.

Hiroshima survivor on Riverside Drive.

The most confusing clock in New York.