Washington, D.C. is situated in a topographic bowl.  The bottom of the bowl, where the White House and Capitol are located, is in the floodplain of the junction of the Anacostia and Potomac Rivers.  Extending out from the floodplain is a series of rising river terraces. These high ridges nearly surround the city (the “bowl”) and are where the earthen Civil War fortifications were strategically built.  This fort “circle” could defend the city from any enemy approach. more...