On the left of the front, where the U.S. 27th Division began at a disadvantage, none of the objectives was met on the first day and the Americans suffered severe losses. The 107th Infantry Regiment suffered the worst casualties sustained in a single day by any U.S. regiment during the war. Rather than leapfrogging through the Americans, the Australian 3rd Division became involved in a desperate fight for positions that should already have been captured had Monash's plan run to timetable. Despite some individual acts of heroism the lack of progress on the left of the front had an adverse effect on the progress of the right of the front too. As the American 30th Division and then the Australian 5th Division moved forward whilst the units to their left did not, they had to contend with German fire from the side and rear as well as from ahead. An added difficulty was thick fog across the battlefield in the earlier stages of the attack which led to American troops passing by Germans without realising that they were there, with the Germans causing severe problems to the Americans following the assault wave. Fog also caused problems for infantry/tank cooperation. The 30th Infantry Division broke through the Hindenburg Line in the fog on 29 September 1918, entering Bellicourt, capturing the southern entrance of Bellicourt Tunnel and reaching the village of Nauroy, where Australian troops joined them to continue the attack.