The United States' first transcontinental automobile road came to its end at this spot in San Francisco's Lincoln Park.

A landscape decorated with enormous skull sculptures.

These hooded graves are the only of their kind in the United States.

Where hikers on the Tecumseh Trail can exchange a dirty sock for a free geode.

Between 1930 and 1946, a tobacco farmer laid his beloved horses and mules to rest in this small patch of pine forest.

Walk in the footsteps of the famed astronaut at Purdue University.

Tombstones carved to look like tree trunks are used for multiple generations of family members.

Staves, storm-calling, and of course, necropants.

New York City's smallest piece of private property.

This small memorial honors a ferocious feline and local hero.

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

A traveling postal dog covered 48 states and more than 140,000 miles, and he lives on as taxidermy, patched up with a rabbit's foot and a pig's ear.

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

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

After 800 years, Europe's oldest elm tree has met its end.

The little tuxedo cat survived the trip, then languished in obscurity.

This "common-as-dirt" museum celebrates the glory of normalcy.

A mysterious monument where a woman who records say never existed was burnt alive for being a witch.

A self-built castle made by a mysterious man.

The severed head of a 17th-century Irish martyr lies within an intricate golden shrine.

This stretch of highway is said to be haunted by ghosts of settlers whose graves were paved over.