The national park was once a plantation estate.

This unique historical monument features large concrete spheres designed to resemble fallen stars.

At 207 feet, one of the world's longest continuous escalators.

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

Before Nixon, "watergate" meant canals.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

The first memorial dedicated solely to the Black troops who fought for the Union.

This unacceptably tall building was the real reason for Washington, D.C.'s skyscraper ban.

This imposing Masonic temple a mile from the White House was the first public library in Washington, D.C.

Behind an abandoned storefront is an example of pioneering 1930s gas station architecture.

A building shaped like the Army Corps of Engineers logo, because why not?

When it opened during the final years of the embargo, all the drinks and cigars were free.

When it comes to handsignals (and colonialism) rock always beats scissors.

The most accurate timepiece in the world.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

Every drop of D.C. tap water flows through this old waterworks.

Brain collection and database that narrows the gap between man and animal.

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

An astounding collection of medical specimens, including bits of President Lincoln.

FDR's Art Deco hospital tower was hopelessly inefficient.

She stares out across six lanes of traffic, clutching a musket and infant with determination.

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