This massive collection of British military artifacts includes the heartbreaking personal letters of the men in the trenches of WWI.

A man-made island in scenic San Francisco Bay.

A massive sea stack famous for its appearance in The Goonies.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

San Francisco's newly reopened hands-on science museum.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

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

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

These four islands right offshore have waterfalls, colorful lights, fancy buildings, and a secret purpose.

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

An overlooked memorial honoring the local Washington residents who died in World War I.

The naval commander’s proudest moment in battle is memorialized in this unique tomb at Arlington Cemetery.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

The rogue roots are gradually consuming some of the historic marble grave markers.

These experimental weapons brought World War II to Nebraska as well as 26 other U.S. states.

Contractors in this Oregon town have been stamping their names in sidewalks since 1908.

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

An obelisk commemorating Lincoln's role in connecting the coasts.

This graveyard is the eternal home of the residents of a vanished California town.

This church built atop a gas station promises to "equip you for the next stage in your life’s journey."

FDR's Art Deco hospital tower was hopelessly inefficient.