Upon Napoleon's return to power in March 1815, many states that had opposed him formed the Seventh Coalition and began to mobilize armies. Wellington and Blücher's armies were cantoned close to the north-eastern border of France. Napoleon chose to attack them in the hope of destroying them before they could join in a coordinated invasion of France with other members of the coalition. Waterloo was the decisive engagement of the Waterloo Campaign and Napoleon's last. According to Wellington, the battle was "the nearest-run thing you ever saw in your life". The defeat at Waterloo ended Napoleon's rule as Emperor of the French, and marked the end of his Hundred Days return from exile. Napoleon abdicated 4 days later, and on the 7 July coalition forces entered Paris.
I entered the present day Waterloo to try to get the feel of the day with a group of colleagues and did "the tour" seeing the battlefield, Napoleon and Duke of Wellington's headquarters, the church in the town of Waterloo, many museums and even climbed up the Lion's Mound.
Here are a few photos of the visit.