Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

The highest point in South Dakota contains the ashes of Valentine McGillycuudy, the "Holy White Man."

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

A museum dedicated to the alleged Roswell Incident.

A blacklight journey through a celestial art exhibit.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

A place where the laws of nature seem to have gone completely berserk... but of course haven't.

One of the smallest towns in the United States.

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

This Chinese-style quartz sundial was saved in its final hour.

A technicolor place of worship for Elevationists.

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.

This museum offers an actual time machine back through Colorado's past.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

The history of funerals and funerary customs.

This rare triple-jurisdiction drawbridge passes through Virginia, Maryland, and Washington, D.C.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

A line of blue paint marks the route of the inaugural parade.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

The trials and tribulations of marking Poe's grave.

A wunderkammer hidden on the top floor of the Hartford statehouse.

This historic church is named for abolitionist Henry Ward Beecher and the ruse to arm his fellow abolitionists.

A cannon designed to fire an atomic warhead.