An otherwise quiet campground becomes a bustling medieval town for two weeks every year.

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

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

This elaborate towering structure was once famed for its revolutionary height.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

The world's largest military aircraft cemetery.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

America's only nuclear missile silo open to the public.

A historic arena where the Beatles played their first concert in the U.S.

This free, take-a-book shop seems like a trick but isn't.

Once America's tallest structure, now a Baltimore landmark.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

An abandoned factory along the Mississippi coated by a giant mural.

The rusting remains of the largest assembled WWII fleet on the West Coast.

Mysterious 500-year-old tapestries depict a unicorn hunt.

A small granite block at this monument's base is the only part of Lincoln's Tomb outside of Illinois.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

A breathtaking array of ancient Pueblo structures and artifacts counterintuitively preserved by neglect.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

Legends surround this jagged rock formation in the New Mexico desert.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

The king of U.S. high points towers over every other peak on the continent.

The highest point in Washington state is a volcano covered in glaciers.