Two small markers remember the Alamo's feline protectors.

Amazingly detailed marble cinerary urns that once held the cremains of Roman elite.

A tall smoke stack and boarded-up buildings are all that's left of the pioneering plant.

A gorgeous garden oasis with winding paths, stone bridges, and a troubling history.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

Conflicting markers on its floor tell a tale of two city centers in San Antonio.

A massive, majestic mammal watches over pedestrians from his perch atop a former B.P.O.E. lodge.

The only remaining African American schoolhouse in northern Virginia is now a museum dedicated to formerly enslaved people.

The only U.S. Senator to die on the field of battle is buried in San Francisco but memorialized at Balls Bluff Regional Park.

Alexander Milliner, a favorite of General Washington, is interred at Mt. Hope Cemetery along with 80 other Revolutionary War veterans.

Where the Millerites gathered to watch the end of the world in 1844—and left disappointed.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

The only remaining historic maritime signal station in the United States.

Its unique collection details the history of the state's svelte railroads.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

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

Yo, Adrian!

This elaborate towering structure was once famed for its revolutionary height.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

This little brick tunnel built by Confederate forces was used to conduct surprise attacks on the railroad.

This small pedestal marks the spot of the first lot of land sold in Alexandria, Virginia in 1749.

A touching tribute to a local hero who made sure his neighborhood stayed clean.

A total of 14 men held the title of "president" before George Washington—their historical legacies are enshrined in the lobby of a hotel.