Great War Tanks
While tanks were a technological advance and came to replace the cavalry, they did not perform well on all terrains. To cross trenches and craters, each tank carried, on its roof, a rolled up fascine — a 10x6 foot bundle of fence posts, reinforced with steel pipes through the middle. When approaching a trench, the fascine was laid over the hole, so the tank could cross. The infantry followed behind, moving invisibly under cover of the tanks.