A scenic fort on the harbor protected Philadelphia from an attack that never came.

This statue honors the author's groundbreaking family story.

Go take a picture with the inventor of the daguerreotype photographic process.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

Nassau Hall has served as army barracks, a museum, and played a key role in the American Revolution.

A local prank turned town icon.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

Heron, whitewater rapids, and urban industrialism all add to the beauty of this concrete nature walk.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

The fairy tale castle of the "fairy-tale king."

The prototype for all Nazi concentration camps.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Turning night into day in Victorian-era Austin to thwart a serial killer.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

This unassuming retro burger joint was billed as “diner of the future” at the 1939 World's Fair.