An extensive collection of fine art devoted to man's best friend.

Avoid gangster interaction while window-shopping.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

This innocent-looking townhome is actually a subway exit.

This industrial chimney looks rather out of place, isolated in the middle of an attractive woodland.

Anna Anderson spent most of her life claiming to be the lost Romanov child Anastasia.

A large boulder marks the place where the island of Manhattan was purportedly "sold" to the Dutch.

The story behind this beloved toy—named for Theodore Roosevelt and owned by his grandson—is more complicated than you might guess.

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.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

This unassuming passageway played a key role in one of the most important events in U.S. history.

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

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

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Perhaps the most scandalous statue of America's first president.

The most decorated dog of World War I is preserved in the Smithsonian.

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

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

A cemetery for only coon hounds in northwest Alabama.