A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

The oldest continuously operating fish market in the United States.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

Washington's iconic carousel has a nice piece of Civil Rights history.

The United States Capitol's former columns still stand.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

The rogue roots are gradually consuming some of the historic marble grave markers.

A Florida college boasts the world's largest single-site collection of structures designed by Frank Lloyd Wright.

A replica of one of the more than 15,000 civilian lookout towers that lined the U.S. coast during World War II.

Remarkably realistic Florida shoal bass "swim" inside this large globoid sculpture.

The only Florida state park with publicly accessible caves.

This now-deactivated naval base defended the Florida coast for centuries.

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

Live long and prosper in Tennessee.

This historic train station has been converted to a locomotive themed hotel.

A wealth of local folk art, antiques, and curios, without ever leaving your car.