Q. In which year, the “Hundred Days War” happened?
Answer: 1815
Notes: The Hundred Days War, also known as the War of the Seventh Coalition, marked the period between Napoleon's return from exile on the island of Elba to Paris on 20 March 1815 and the second restoration of King Louis XVIII on 8 July 1815. This period saw the War of the Seventh Coalition and includes the Waterloo Campaign, the Neapolitan War as well as several other minor campaigns. This set the stage for the last conflict in the Napoleonic Wars, the defeat of Napoleon at the Battle of Waterloo, the second restoration of the French kingdom, and the permanent exile of Napoleon to the distant island of Saint Helena, where he died in May 1821.