(Main article: Battle of the Ancre Heights) Regina Trench (Staufen Riegel) was a German trench dug along the north-facing slope of a ridge running from north-west of the village of Le Sars, south-westwards to Stuff Redoubt (Staufenfeste), close to the German fortifications at Thiepval on the Somme battlefield. It was the longest such trench on the German front during the First World War. Attacked several times by the Canadian Corps during the Battle of the Ancre Heights, the 5th Canadian Brigade briefly controlled a section of the trench on 1 October but was repulsed by counter-attacks of the German Marine Brigade (equivalent to an army division), which had been brought from the Belgian coast. An attack on 8 October, by the 1st Canadian Division and the 3rd Canadian Division on Regina Tren