The Circumfence is a fence that stretches along about a third of The Discworld's circumference, around a large stretch of the Rim Ocean, and about five thousand miles to either side of the continent of Krull. The fence is actually a rope suspended a few feet above the surface of the water at the very Edge, supported by stout wooden posts at regular intervals. Smaller ropes hang from the main one at regular intervals to form a crude-looking net, which must nevertheless be effective; it is stong enough to prevent Rincewind and Twoflower from falling off the Edge, and plenty of flotsam (including timber, ships, barrels of wine, bales of cloth and, yes, the occasional Auriental tourist, hopelessly inept wizard and psychotic travel accessory) is collected on it and taken to Krull by salvage fleets. The Circumfence is divided into lengths of one league each, and each length has a lengthman to patrol it. The only named lengthmen are Tethis the Sea Troll and Terton, who we learn absolutely nothing about except his job.