Tunnels in Washington, D.C.

Once a sewer culvert, this road tunnel now offers cyclists and pedestrians a subterranean stroll under the C&O Canal.

An 18-mile-long tunnel for sewage waste will soon wind within the bowels of Washington, D.C.

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

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

These abandoned waterworks are crumbling into the Potomac River.

The tunnel under the Capitol Building where Congress takes out its trash.

A painfully obvious spy house sits right across the street from the Russian Embassy.

100 years later, they're still down there.

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

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.