This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

Solar powered Spectacle Island features all-green facilities.

Second largest wastewater treatment plant in the country.

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

This hotel was the site of major events in sports and radio history. It was also used as a detention center during World War II.

A luxury hotel constructed out of a former jail.

The former site of an all-but-forgotten colonial landmark is now remembered by an often overlooked bas relief.

Sacks of potatoes, made of cast stone, mark where the iconic potato sheds once stood along the river.

This giant Boston statue of Mary is standing on a globe to show her power over the universe.

Museum dedicated to awful artwork.

Dim sum, served in a grand old theater.

One of the oldest used bookstores in the U.S. has been selling antiquarian treasures since 1825.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

Naturally formed white marble arch housed in an abandoned marble quarry from the 1800s.

This abandoned neighborhood is now a park filled with beautiful trees, wildflowers, and hints of its past.

Resonating tubes make music from highway overpass.

A war memorial that appears to ascend from its forested setting.

Locals purchased this abandoned quarry in order to make sure it continues to be overgrown.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

Sip creative cocktails in the former vault of the Riggs Bank.

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

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

The site of the climactic scene from the classic horror film is now a historic landmark.