The walls of the iconic dome are hollow and have a secret stairway.

This grand gothic brewery has been pumping out suds for over a hundred years.

A world of whimsy and wonder aboard a one of a kind historic landmark vessel.

The home of aviation trailblazers, in a remote corner of the big city.

Once America's longest-manned military fort, now an abandoned hulk.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

The last of Philadelphia's wood-paved streets is now a landmark of terrible engineering.

Alexander Hamilton’s creation caused quite a bit of controversy.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

Yo, Adrian!

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

Enjoy a slice while browsing the world's largest collection of pizza memorabilia.

The origin of this mechanical boy was a mystery until he revealed his maker by writing it in perfect cursive.

A rare view of a preserved Victorian science museum.

World's first "penitentiary," meant to be humane, drove men insane.

Literal "money laundering."

America's Most Wanted's set resides in this tribute to the history of crime and punishment.

Amid the sprawling Defense Intelligence Agency Headquarters is one of Washington's least accessible museums.

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

The district's only illusionarium supports free writing programs for local students with every purchase.

The school tested mustard gas for the U.S. Army during World War I.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.