Frank Lloyd Wright built this suburban synagogue late in life, but it stands among his most iconic masterpieces.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

A secret greenspace hides atop a Capitol parking garage.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

For 60 years, the academy had no permanent location until members voted Washington D.C. as its forever home.

An ear-piercing buzzer calls lawmakers to a vote with a series of long and short rings to form coded messages.

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

‘Bush the old fire dog died of poison July 5th, 1869. RIP.’

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

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

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

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

Legend has it that President Grant’s frequent drinking in the lobby gave rise to the term “lobbyist.”

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

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

Largest Roman Catholic church in North America.

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

A nostalgic bibliographic gem.

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

The walls of the iconic dome are hollow and have a secret stairway.

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