A museum dedicated to the history and exploration of both popular music and science fiction.

A giant Troll lurks under one of Seattle's oldest bridges.

A walk through the historic city center, under the streets of Seattle.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

The only recreation of William Shakespeare's indoor playhouse.

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A former major munitions plant that has been converted into a sprawling art space.

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

Herbert Hoover's "Brown House" rural presidential retreat was a PR disaster amid the start of the Great Depression.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Hidden for 165 years inside a building designed by Thomas Jefferson are the remains of what may be America's first educational chemistry lab.

This historic mansion was built as a symbol of love between a husband and wife.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.