Moat
Moats were deep and wide trenches, usually filled with water, to provide a barrier against attack upon castle ramparts or other fortifications.
Often streams were diverted in the Middle Ages to fill the ditch. Moats required upkeep. They had to be dredged for debris which could potentially form a traversible bridge from one side to another.
Bridges spanned across moats in the Middle Ages. At first they were only simple wooden bridges that could easily be destroyed if an enemy was about to breach the fortifications. Later flying bridges and drawbridges were used for moat spans.
Moats sometimes had long woden spikes in them, to prevent enemies from swimming across.
While moats are commonly associated with European castles, they were also developed by North American Indians of the Mississippian civilization as the outer defense of some pike-walled villages. The remains of a 16th century moat are still visible at the Parkin Archeological State Park in eastern Arkansas.
