On June 18, 1815, one of the most famous battles in history took place near a small town in Belgium called Waterloo. Napoleon Bonaparte, the emperor of France, had already been defeated once and sent into exile on the island of Elba. But he escaped, returned to France, and raised a new army in just 100 days. The other nations of Europe, including Britain, Prussia, Austria, and Russia, formed an alliance to stop him. The battle pitted Napoleon's French army against British forces led by the Duke of Wellington. Heavy rain the night before turned the fields into thick mud, forcing Napoleon to delay his attack. This delay gave the Prussian army, led by General Blucher, time to march toward Waterloo. Wellington's troops held their ground all day against fierce French attacks. When the Prussians finally arrived in the late afternoon, Napoleon's army was caught between two forces. The French lines collapsed, and Napoleon fled the battlefield. Within weeks, he surrendered to the British, who sent him to the remote island of Saint Helena in the South Atlantic. He lived there until his death in 1821. The Battle of Waterloo ended 23 years of nearly constant war in Europe and reshaped the continent's borders for decades.