This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Great place to have a drink and a bite to eat in an atmosphere laden with New York's Bohemian past.

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

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This 19th-century Hamptons windmill was once home to modernist painter Agnes Pelton.

The seat of Buffalo government is a gorgeous Art Deco palace.

The longest continuous underwater road in North America was built at the insistence of Franklin Roosevelt.

The gilded vestiges of a sterling department store can still be found in a Brooklyn shopping center.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

Bits and pieces from the ill-fated Donner Party's winter cabins.

A breathtaking 19th-century trail overlooks Lake Tahoe.

Where a railroad loops under or over itself to rise or drop more than 70 feet in a short distance.

Exotic feline breeding compound and conservation center.

Thousands of turbines whir at at the origin of North American wind power.

California's oldest wind harp represents a historic piece of America's Danish history.

Concrete strongholds stand guard over the Golden Gate.

Santa Monica's oldest restaurant, decorated with set pieces from the Mutiny on the Bounty.

Housed in a memorial lighthouse, this museum relays the history of surfing, beginning with the antics of royal Hawaiian teenagers.

The beautiful behemoth is one of the largest trees of its kind in the United States.

Oldest building in California still in use.

This turn of the century masterpiece has a mysterious goaty interloper.