The blinking light atop the iconic landmark has been sending secret messages for decades.

This bank is widely believed to be the inspiration for the offices of Philip Marlowe, the hardboiled detective featured in a number of Raymond Chandler's stories.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A charming desert roadside bakery that produces 10 times more bread daily than it has residents in its town.

All that remains of a magnate's dream home is a historic gate and an abandoned public pool.

This magnificent herd of stampeding elephants has been frozen in time for over a century.

The ancient past meets the retro-future at these dinosaur tracks that are protected by a geodesic dome.

Journey inside the bowels of this sperm whale sculpture.

Long the exclusive domain of birds and vagabonds, this little-known Central Park peninsula is open to the public once more.

Though the case is scorched and the buttons half-melted, this hardy handheld gaming device can still run a game of Tetris.

This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

A celebrity from the late Cretaceous period.

The oldest building in the District of Columbia was preserved because of a mistaken connection to George Washington.

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

The United States Capitol's former columns still stand.

Once a sewer culvert, this road tunnel now offers cyclists and pedestrians a subterranean stroll under the C&O Canal.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

The first memorial dedicated solely to the Black troops who fought for the Union.

The oldest continuously operating fish market in the United States.

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.

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

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

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