The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

Corn-inthian columns with a uniquely American take on neoclassical architecture.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

This groundbreaking 16th-century map is known as "America's birth certificate."

In the middle of a busy airport, a statue honoring the astronaut who told Houston that Apollo 13 had a problem.

One street divides a single town that stands in two U.S. states.

This 36-foot-tall bronze Lady Liberty holds a real flaming torch.

A striking lighthouse with views of the Gulf of Mexico and of a military air show.

This Pennsylvania structure, the oldest building in Gettysburg, was once a stop on the Underground Railroad.

Experience the pivotal Civil War battle at this interactive museum.

Witness these plains giants that nearly became extinct in the late 1800s.

Hear the roar of the engines and the crowd at this nearly 90-year-old Pennsylvania track.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

The ruins of a town wiped out by the second-largest earthquake in recorded history.

These unusual rooms on wheels are holdovers from the 1960s.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

A monument marks the location of the first successful steamboat demonstration.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.