 Heavy shellfire made the rear ditch untenable, and German forces were able to get between the forts and attack them from the rear.The massive German bombardments drove men into the central massif, where there were insufficient sanitary facilities for 500 men, rendering the air unbreathable, while the German artillery destroyed the forts from above and from the rear.In the Battle of Liège the Liège fortifications fulfilled their role, stopping the German army long enough to allow the Belgian and French armies to mobilize.