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

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

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

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

A luxuriant botanical garden below sea level.

The land is home to swimming ponies and a legendary 18th-century treasure.

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This small-town pizzeria won the Hollywood lottery.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

The second oldest Jewish graveyard in the U.S. is tiny, with connections to George Washington and Henry Wadsworth Longfellow.

Oldest synagogue in the United States.

A 60-room castle constructed by a horse-racing heir.

A railroad magnate's replica village has become home to a genetic seed bank for rare breeds of livestock.

Mysterious stone tower featured in many alternative histories of the New World.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

This Rhode Island mansion was a stand-in for the exteriors of Collinwood in the original "Dark Shadows" series.

Paths are maintained, but trees have taken over plots.

Oldest unrestored plantation house in America that is open to the public.