Obscure Freemasons still live in D.C.’s largest private residence.

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

Where you can hail your favorite fictional commanders-in-chief.

Railroad officials in the early 1900s sought to spare travelers the sight of Roman soldiers’ private parts.

A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Need a hardcopy of the 50-title Code of Federal Regulations? This is the place.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

The romance of early commercial flight still fills this Art Deco destination.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

These unusual rooms on wheels are holdovers from the 1960s.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

Rock face that shares a name with Mary Shelley's famous doctor.

The largest puppetry museum in the United States houses the world's most complete collection of Jim Henson artifacts.

The first integrated firehouse in Atlanta houses a museum on the history of desegregation in the city's fire department.

A colorful square marks the heart of the city's LGBTQ community.

Final remnants of the 1895 Cotton States and International Exposition.

This angular brutalist playground turns playtime into modern art time.

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

Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

This statue of one of baseball’s greatest pitchers looks like something out of a sci-fi horror movie.

A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

One critic described it as "middle Mussolini, early Ramses, and late Neiman-Marcus." Another called it an architectural "natural disaster."

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”