How was Napoleon defeated?

Napoleon invaded Russia in the summer of 1812, resulting in a catastrophic retreat of Napoleon's Grade Armée. One year later, Prussia and Australia joined Russian forces, defeating Napoleon at the Battle of Leipzig. The coalition then invaded France and captured Paris, forcing Napoleon to abdicate in April 1814. Napoleon was forced to exile to the island of Elba.
Napoleon escaped in 1815 and took back control of France. He was defeated again during the Battle of Waterloo in June 1815 and sent to exile by the British to the remote island of Saint Helena where he died in 1921.