Washington Navy Yard and Annex

Historical marker location:

Navy Yard, District of Columbia

( Marker can be reached from the intersection of M Street Southeast and 4th Street Southeast, on the right when traveling east.)

Sentry Tower and Walls

The city was built on a swamp: The area that is now Washington, D.C. was originally a swampy, marshy region along the Potomac River. The construction of the city involved extensive drainage and landfill projects to make the land suitable for building.