There’s a hidden military meme engraved on the World War II Memorial.

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.

The walls of the iconic dome are hollow and have a secret stairway.

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.

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

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

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

Ruins from the Parthenon and petrified wood line the interior of one of the world's most famous monuments.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

A tribute to the pop culture icon overlooks this Washington D.C. intersection.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

Partially submerged Buddha heads freckle Chicago’s neighborhoods.

This whimsical Oz-themed park had a wonderful impact on the surrounding neighborhood.

Statue dedicated to the star of an old television show.

This was once the largest four-sided clock in the world (yes, even bigger than Big Ben).

A journey begins with a single step, and for many, the road-trip of a lifetime started at this Chicago intersection.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

The bugs crawling down the front of this office building are almost as big as a '68 VW Beetle.

A place to eat for on-the-run agents and espionage enthusiasts.

An outdoor urban gallery of large-scale artworks by the world's most influential street artists.

Take a stroll through this centuries-old tunnel of enormous moss-hung evergreens, nestled among the grounds of America’s first public sculpture garden.