This massive redwood tree has a hole in the base big enough to drive through.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

This building at the south end of the boardwalk was once home to the U.S. Life-Saving Service and the U.S. Coast Guard before being rescued itself.

These structures were inspired by both Native American shelters as well as, strangely, an ice cream shop.

A geological mystery on Camelback Mountain.

This collection of Wild West movie memorabilia also claims to hold some secrets of the Lost Dutchman's mine.

This impressive working clock made of 16,000 plants changes its flowers twice a year.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

A wondrous old library overlooking the nation's capital.

The site of the climactic scene from the classic horror film is now a historic landmark.

A nude beach alongside a washed-out road.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

This lush Florida island is home to the ruins of a crooked ship breaker's tiny empire.

A popular place to pick up prehistoric coral fossils from the time when Michigan was an ocean.

The U.S. Supreme Court's secret Cold War relocation facility in the mountains of North Carolina.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

A sacred Ojibwe site covered in pictographs next to Lake Superior.

Accessible only by train, the beauty of Agawa Canyon Wilderness Park is worth the journey.

Western New York's largest independent bookstore doubles as a historical repository of all things Niagara Falls.

Home to over 300 antique cars and motorcycles, including Thomas Edison's Model A.

Shop of curiosities with a dinosaur museum tucked in its basement.

One of the oldest active carousels in the country—but it might be missed by all but the keenest-eyed boardwalk strollers.

A remnant of the last Ice Age, this lake is surrounded by fascinating rock formations.

Visitors are welcome to enter this lush Key West sanctuary to entertain its plethora of rescued parrots.