World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

The historic home still shows the scars from a little run-in with the British in 1813.

A grotesque Fiji merman dwells within this traditional Dutch-style building.

This Pennsylvania structure, the oldest building in Gettysburg, was once a stop on the Underground Railroad.

Remember and reflect at this 9/11 memorial site.

This vintage short line in Amish country runs passenger steam train excursions and still hauls freight.

A comprehensive collection of toy and model trains, largely from the mid-20th century.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

A merry-go-round that became a rallying point for the early Civil Rights Movement.

At the birthplace of American railroading, a world-class collection of historic trains.

Built by the patriotic residents of Boonsboro in a single day.

Captain John Smith thought these cliffs were amazing in 1608 but sharks thought so 20 million years before him.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

This rudder is one of the few remnants of a shipyard that once operated on the banks of the Potomac River.

These unusual rooms on wheels are holdovers from the 1960s.

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

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

A former major munitions plant that has been converted into a sprawling art space.

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