This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

A daily replay of the experiment that proved the rotation of the Earth.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

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

Mesoamerican monoliths and zoomorphic stones covered in royal visages, ancient mythology, and grand celestial events.

This tree was extinct for a thousand years before sprouting again from a 2,000-year-old seed.

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

Oldest existing wire suspension bridge in the United States.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

A real flying saucer, contracted by the U.S. Air Force.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

There aren't too many operational funiculars around, but Pittsburgh has two!

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

The only sea in the world that has no land boundary.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

The statue of John Harvard isn't actually John Harvard—or even, technically, the founder of the school.

Look closely and you’ll notice that the color changes a third of the way up the tower.

The name of this tiny pocket park tucked between two buildings on Manhattan's Upper West Side is Latin for its location: "seventy-one."

The unbelievably opulent home built for an infamous newspaperman.

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