This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

An obscure public service from the U.S. government that redeems burnt, moldy, and soiled old greenbacks.

Home to items never before seen by the public.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

The U.S. Navy’s preposterously detailed mini battleship took 77,000 hours to complete.

One of the largest artillery pieces in the world sits in a Washington D.C. parking lot.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

This stately building in Alexandria, Virginia was built by Freemasons to honor one of their most famous members.

The final resting place of an unidentified revolutionary soldier sits behind a Virginia church.

This enigmatic building features numerous architectural styles.

Colorful boxes placed over the dead are left to rot and crumble.

A high school astronomy enthusiast designed this model of our solar system to be traversed on foot.

While not recognized by Guinness, this chocolate waterfall is likely to be the world's largest.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

This concrete ship has had four careers - World War I tanker, floating amusement park, fishing pier, and artificial reef.

One of the most elaborate displays of Jellyfish is on display at the aquarium.

For almost 100 years, this site of peace and spirituality has existed on the California coast.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

A small canyon with petroglyphs and a seasonal waterfall, only a short hike from the remnants of old Route 66.

A sculpture that resurrected the only tree standing following the devastating 2011 tsunami.

A sobering scientific reminder of the human damage caused by the advent of the nuclear age.