Hollywood's oldest hotel is the site of the first Academy Awards, the birthplace of Marilyn Monroe's career, and the home of Montgomery Clift's ghost.

In 1787, a group of delegates met at this very spot to drink, be merry, and ratify the Constitution of the United States.

This 40-room dwelling tucked within a cliff was built by the basin's prehistoric residents.

A living snapshot of a different time in America is preserved and maintained by a community of volunteers.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

Constantly maintained, this organ is playing a six-century long composition by John Cage.

Life-size bronzes of the Grinch, Cat in the Hat, Yertle the Turtle, Sam-I-Am, and the Lorax—and the author himself.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

An Industrial Revolution-era public work that purified water using nothing but sand.

Now nearly abandoned, Kaskaskia was once the capital of Illinois and one of the most important towns on the upper Mississippi.

This nine-story building is the oldest standing skyscraper in D.C.

Bison, America's national mammal, are staging a slow comeback in Ohio's prairie parkland.

The stone marker that Mason and Dixon placed at the eastern end of the famous north-south border they surveyed.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

A reconstructed medieval gateway that was the magnificent entrance to the capital city dating back to 1037.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

The show's fictional Korean medical camp was created in the Santa Monica hills.

The great Danube river starts here.

This stone tower marks a lookout point over the historic Washington Crossing, and maybe some buried treasure.

The famous bell was secreted away and hidden in a church in Allentown during the British occupation of Philadelphia.

You would never guess that before World War II this lonely field was a bustling German city.