A centuries-old church stands as a testament to Boston's "father of architecture."

FDR's Art Deco hospital tower was hopelessly inefficient.

An overlooked memorial honoring the local Washington residents who died in World War I.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

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

The little-known, 300-year history of the area includes former lives as a bustling tobacco port, parking lot, and industrial dump.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

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

This lovely pocket park is one of the most under appreciated in D.C.

A celebrity from the late Cretaceous period.

The national park was once a plantation estate.

Art deco landmark on the outskirts of Washington, D.C.

A rotating cast of guys and dolls in front of a Washington, D.C. building.

The most accurate timepiece in the world.

The oldest continuously operating fish market in the United States.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

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.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

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

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

The United States Capitol's former columns still stand.

The statue of John Harvard isn't actually John Harvard—or even, technically, the founder of the school.