World War I: The Battle of Charleroi, a successful German attack across the River Sambre that pre-empted a French offensive in the same area.

World War I or the First World War, also known as the Great War, was a global conflict between two coalitions: the Allies and the Central Powers. Main areas of conflict included Europe and the Middle East, as well as parts of Africa and the Asia-Pacific. There were important developments in weaponry including tanks, aircraft, artillery, machine guns, and chemical weapons. One of the deadliest conflicts in history, it resulted in an estimated 30 million military casualties, plus another 8 million civilian deaths from war-related causes and genocide. The movement of large numbers of people was a major factor in the deadly Spanish flu pandemic.

The Battle of Charleroi or the Battle of the Sambre, was fought on 21 August 1914, by the French Fifth Army and the German 2nd and 3rd armies, during the Battle of the Frontiers. The French were planning an attack across the Sambre River, when the Germans attacked first, forced back the French from the river and nearly cut off the French retreat by crossing the Meuse River around Dinant and getting behind the French right flank. The French were saved by a counter-attack at Dinant and the re-direction of the 3rd Army to the north-west in support of the 2nd Army, rather than south-west.

The Sambre is a river in northern France and in Wallonia, Belgium. It is a left-bank tributary of the Meuse, which it joins in the Wallonian capital Namur.