These bodies of water surrounding fortresses reduced the risk of tunneling. One of the most serious forms of attack was to undermine part of a castle. The ‘miners’ were called Sappers. They would dig a tunnel underneath one of the corners using timber props (‘ sapping’), and then fill the tunnel with wood and set it on fire. This would cause the corner to collapse. The structure would be weakened and the weight of the castle would bring the walls caving in and that section would collapse. Other reasons for a moat were so that attackers could not wade across for fear of drowning in the deep waters, and for fear that it made them an easy target for the castle guards. Travel with Far Horizons to castles all over the world!