This 1920s Dutch barge is now a floating bookstore.

Dedicated to a U.S. Army lieutenant colonel who was also a bird watcher and artist.

This abandoned sea fort has become an accidental bird sanctuary.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

An isolated island home to one of the oldest English-speaking communities in the region and Maryland's state dessert.

Bizarre Cavern.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

These five Art Deco homes were meant to solve the "small house problem."

Its diverse collection of computers and technology spans the ages.

Giant acorn-shaped 19th century gazebo from which suburban Washingtonians gazed upon the original "silver" spring.

The world's oldest continuously operating airport was founded by the Wright Brothers.

Electronic inventions that resulted in products and systems we use every day are on display in this labor-of-love museum.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

A priceless collection of the Nation's cryptologic history.

Extraordinary objects lurk in this quintessential regional museum.

This cannonball stands as a reminder of the final act of a fleeting governor amidst a revolution.

This museum sits on the site of a decommissioned military communications base.

A genuine Tudor manor transported piece by piece from England.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

Exact replica of the ancient monument, but much, much lighter.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.