Today marks the 200th anniversary of the Battle of Waterloo, in which Napoleon Bonaparte suffered his final defeat.
It marked a turning point for Europe - in a very real sense, the seeds of the present-day European Union may be said to have been sowed at the Congress of Vienna, which ended nine days before the battle.
The Battle of Waterloo was, in fact, only one of several that took place from June 15-18. The campaign began when French forces drove back Prussian pickets and crossed the Sambre River. The following day the French fought Wellington's British forces at the Battle of Quatre Bras, driving them back, and the Prussians at the Battle of Ligny. Wellington retired towards Waterloo, where he set up his line of battle on the evening of June 17th, while Marshal Grouchy of France pursued the Prussians, but crucially failed to cut them off. While Wellington was fighting Napoleon's main body at Waterloo the following day, the Prussians fought off the French at the Battle of Wavre. Grouchy could not prevent the main body of the Prussian Army joining Wellington on the evening of July 18th, just in time to ensure victory at Waterloo.
Many participants recorded their memories of the battle. The Telegraph has a good summary of some of the contemporary accounts. Among them is this one from Private Leonard of the 2nd Nassau Regiment, recalling the fifth French assault on the Château d'Hougoumont.
The hornbeam trees of the garden alley, underneath which we stood, were razed by the immense cannonade and so were the beautiful tall trees along the outside of the farm. Walls were collapsing from both the heavy bombardment [and] the severe thunderstorm that raged above us, the likes of which I have never experienced before; one could not distinguish one from the other. The skies seemed to have been changed into an ocean of fire; all of the farm's buildings were aflame. The soil underneath my feet began to shake and tremble, and large fissures opened up before my very eyes.
Casualties were heavy on both sides. According to Wikipedia:
Waterloo cost Wellington around 15,000 dead or wounded and Blücher some 7,000 (810 of which were suffered by just one unit: the 18th Regiment, which served in Bülow's 15th Brigade, had fought at both Frichermont and Plancenoit, and won 33 Iron Crosses). Napoleon's losses were 24,000 to 26,000 killed or wounded and included 6,000 to 7,000 captured with an additional 15,000 deserting subsequent to the battle and over the following days.
Since Waterloo, British and French forces have never again clashed on the battlefield.