Try not to get slimed in Tribeca.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

A take-out restaurant that only serves cuisine from countries with which the United States is in conflict.

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

It may appear to be a fancy junk yard, but each item has a story to tell and a lesson to impart.

The aggressively banal name of this underground fortress of bureaucracy does little to evoke its truly surreal existence.

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

The only statue of its kind to commemorate Washington's beginnings as an officer of the British Colonial Militia.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

With 3,000 bikes on display, the world's largest bicycle museum includes some famous rarities.

Once on display alongside a giant Gumby, it’s as tall as a nine-story building when fully extended.

The residents of the Neighborhood of Make-Believe live without much fanfare within the Pittsburgh Children's Museum.

The first American department store, and home to the largest operating musical instrument in the world.

The universally beloved children's television figure is interred on a high hilltop in one of western Pennsylvania's oldest cemeteries.

A train station that was abandoned by the coal industry and was later converted into a cocktail bar.

Proto-CIA agents trained with grenades in the sand traps and fired machine guns from the fairways.

The U.S. government built the million-pound stack of steel during the Space Race.

The wooded estate of the Forest Service employee responsible for D.C.’s cherry blossom trees.

A suburban museum tells the story of a historic transportation network and even provides rides in antique trolley cars.

This massive swimming pool is the high tech home to the human-powered submarine races.

A relic of FDR's brief foray into utopian urban planning.

One of the only memorials dedicated to journalists who died in combat.

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

This suburban house is made of dirt, and almost sparked a revolution in home construction.