Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

A heroic pigeon that, through a barrage of gunfire, delivered a message that saved over 100 lives in World War I.

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

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

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

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

This taxidermy horse was a Civil War hero.

The innocent intentions of this monument are somewhat lost in the sculpture's muscled imagery.

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

Atop this media building, two hives containing more than 30,000 bees keep the surrounding area vibrant.

A spectacular tribute to statesman and philanthropist Andrew Mellon.

After James Madison's death, his wife and former First Lady Dolley Madison lived in this yellow building near the White House.

A miniature version of the ship that took John Cabot from Bristol to Newfoundland.

This bronze sculpture was inspired by a photograph of Martin Luther King Jr. and his wife embracing after he won the Nobel Peace Prize.

The competition: breathe deeply as long as you can.

Unrepaired walls from a 1920 anarchist bomb attack.

An artist's cute bronze subway sculptures belie his violent artistic past.

An archway adorned with vulnerable flora and fauna.

A 15th-century whalebone is tucked away in an unassuming corner of this medieval church.

The only Leonardo Da Vinci painting in the Western Hemisphere.

Dedicated to a colonial woman who was hanged for being a Quaker.

Lie in a hammock where George Washington stood.

The East Village tenement from the cover of Led Zeppelin’s 1975 album has a tea shop on the ground floor.

An 18th-century religious argument etched into stone.