The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

The world's largest rose bush has literally outgrown the pioneer museum it was planted behind.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

Time travel with sweets across history at this research-based candy store.

Thomas Jefferson's estate is home to hundreds of varieties of historic fruits and vegetables.

The oldest military monument in the United States.

Just outside the Naval Academy, Hell Point is a historical marker that could easily be the point where failed students wait for the bus.

This statue honors the author's groundbreaking family story.

A giant time capsule not scheduled to be cored until 2040.

A monument marks the location of the first successful steamboat demonstration.

A geological mystery on Camelback Mountain.

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

The only diamond mine in the world where you can keep what you find.

The outcropping is graffitied with the name of the beloved musical Muppet television series.

The state bird of New Mexico, constructed entirely out of garbage.

This quirky hot springs town known to locals as "T or C" was named after a radio show.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

This beloved marketplace mascot poops money and grants good luck.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Dramatic river bend surrounds a natural red-rocked pedestal.

Contrary to popular belief, this secluded statue doesn't represent Pennsylvania's founder.