A Civil War Museum with some notable medical antiques.

A priceless collection of the Nation's cryptologic history.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

A museum dedicated to exhibiting remarkable outsider art.

Crammed into a Baltimore row house is an oddities shop that sells everything from skulls to dead insects.

Eighteen miniature death-scene dioramas.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

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

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

Washington's iconic carousel has a nice piece of Civil Rights history.

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

Home to items never before seen by the public.

The ruins of an abandoned 18th-century town that is slowly being reclaimed by the forest.

The author of Uncle Tom's Cabin was neighbors with Mark Twain while living in this Connecticut home.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

A former copper mine which became a truly unsuccessful prison.

The former home of Samuel Clemens and family remembers the happiest period of the author's life.

What was meant as an innocent piece of art has earned a reputation as the "mansplaining sculpture."