France was invaded in 1940 and the 7th Panzer Division, commanded by Rommel, entered Normandy. The objective being the capture of the Port of Cherbourg, the centre of Manche was bypassed as the German Army occupied Saint-Lô, a strategic crossroads, on the night of 17 June 1940.
During the Liberation, Saint-Lô suffered two series of air attacks during the Battle of Normandy. The first was the bombardment of the city by the Americans during the night of D-Day 6–7 June 1944. The first air American strike killed almost eight hundred civilians. Allied planes continued to attack the power plant and rail facilities daily for a week.
A second series of air attacks began on 17 July, during the Battle of Saint-Lô. This time the city was bombed by the Germans. As a main transport center, the city was a nexus of military activity starting Battle of Normandy and on to the breakout from Normandy, Operation Cobra. As a result of air and ground attacks, Saint-Lô was almost totally destroyed (90-95% according to common estimates). The city was dubbed "The Capital of the Ruins" by Samuel Beckett. Saint-Lô was one of the key cities to the opening of the Falaise Gap, which ultimately allowed Allied forces to expel the Germans from northern France.
Saint-Lô received the Legion of Honour [fr] and the Croix de Guerre 1939-1945 on 2 June 1948 with a citation for "capital of the Manche Department which has retained full confidence in the destiny of the country. Suffered on the night of 6–7 June, with a heroic calm, an air bombardment to such a point that its inhabitants could consider themselves as citizens of the capital of the ruins". These awards would be given on 6 June by President Vincent Auriol. The two communes, now absorbed from Sainte-Croix-de-Saint-Lô and Saint-Thomas-de-Saint-Lô, were also decorated with the Croix de Guerre 1939-1945 on 11 November 1948.