This once-grand marvel of engineering is now 41 miles of scenic hiking trail.

100 massive sculptures in the Hudson River Valley.

Creek water that starts here has a 50/50 chance of ending up in the Atlantic or the Pacific.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Manatees congregate around a power plant's discharge canal where the water is especially warm.

This rural community has attracted both scientists and techno-refugees due to its federally-mandated lack of technology.

A tradition unlike any other, this marks the site of the annual Groundhog's Day tradition.

The house that Frank Lloyd Wright "(shook) out of his sleeve at will" at the age of 86.

Memorializing an American tragedy of massive proportions.

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

World War II bunker still standing on the New Jersey beach.

A mining town once rife with murderous disputes over its copious treasures now creates income as a popular spot for photo shoots.

The world's largest military aircraft cemetery.

A geological mystery on Camelback Mountain.

A working cattle ranch with remarkably well-preserved prehistoric petroglyphs and ancient ruins.

Ancient pueblos built into the base of a natural canyon wall.

Once the product of an inexplicable gold strike, this ghost town is now home to one man and his love of classic machines.

On the outskirts of a reborn ghost town, a decaying post office remembers the bad old days.

A Wild West jailhouse that slid down the mountainside.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

A spiritual vortex among the red rocks in Sedona.

In Tucson a giant metal snake helps pedestrians cross a busy highway.