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.

A super-sized promotional trick that is now a D.C. landmark.

An atomic bomb-proof strongbox protects the U.S. Constitution from terrorists and thieves.

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

A haunting tribute to pioneering photographer Clover Adams.

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

Largest Roman Catholic church in North America.

A nostalgic bibliographic gem.

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

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

The most decorated dog of World War I is preserved in the Smithsonian.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

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

The site of the climactic scene from the classic horror film is now a historic landmark.

The United States Capitol's former columns still stand.

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

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

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

A former major munitions plant that has been converted into a sprawling art space.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.