The National Park Service’s best-kept secret with views that rival any in D.C.

Through the decades, Black music stars have performed at this historic hub for music and the arts.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

This sandwich shop has a century-old elevator behind a sheet of plexiglass.

This robust fence in front of a historic Georgetown home is likely made from hundreds of recycled Revolutionary War firearms.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The unique traffic pattern named for an influential urban planner is also known as the Pedestrian Scramble.

This historic boathouse was constructed using salvaged lumber from burned barns.

A small token of gratitude from freezing cold journalists who were given a warm haven while covering JFK's inauguration.

An 18th-century townhouse that once hosted guests of the president.

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

Government testing at the asylum briefly explored using marijuana as a "truth serum" on Nazi prisoners of war.

The oldest continuously operating fish market in the United States.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

This Civil War monument was designed by an eccentric architect and Gettysburg veteran.

This monument marks the beginning journey of a wounded soldier's leg that ended up almost two states away.

Home of the only civilian casualty at the Battle of Gettysburg.

The beloved, war-tested mascot of a Union regiment graces their battlefield monument.

Walk through the history of American pop culture.

Named for a Greek oracle that interpreted the words of Zeus, this beautifully-restored manor home was once home to the architect of the Marshall Plan.

Every weekend, people gather here for a brief chance to see their loved ones on the other side of the United States–Mexico border.

This celebration of Latvia’s freedom and independence avoided demolition over half a century of Soviet occupation.

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

The oldest housing complex in Riga is a mini timeline of architectural trends.