Double Ditch

Double Ditch, also known as the Double Ditch State Historic Site, Burgois Site, 32BL8, Bourgois Site, and Double Ditch Earth Lodge Village Site, is an archaeological site located along the Missouri River north of Bismarck, North Dakota, United States. It earns its name from the two visible earth mounds that outline the site, but archaeological survey found that there are four ditches total.

• http://en.wikipedia.org/wiki/Double Ditch