D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

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

An overlooked monument to the celebrity gangster who helped put the sin in Sin City.

An exotic wildlife habitat right off The Strip.

One of the world's tallest Ferris wheels takes visitors high above Las Vegas in a spinning party room.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

This statue of the "father of television" stands prominently in the United States Capitol.

The tunnel under the Capitol Building where Congress takes out its trash.

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

The privately owned cemetery that holds room for Washington's finest when they step down from life.

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

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

A collection of fanzines, recordings, and documents detailing the rise and influence of the feminist punk movement.

A semi-scholarly approach to sex.

World's first "penitentiary," meant to be humane, drove men insane.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

The 28-foot granite map plots the locations of 40 theaters in New York City.

There must be a pun in this haystack somewhere...

The New York hotel where tragic visionary Nikola Tesla spent his final hours, destitute and alone but for the pigeons.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

The humble field where the first Major League Baseball game was played.

These lush botanical gardens employ the most purrfect pest control force.

A field of nothing but boulders which resembles a giant's gravel driveway.