Battle Abbey Ruins – Battle, UK
In 1066 A.D., William of Orange, the Duke of Normandy fought the Battle of Hastings against the English army at this location. During the fight, King Harold took an arrow directly to one of his eyes and died, and William took the throne. The "modern" history of England pretty much starts with that event.
As penance for the death of Harold, William built an abbey at the battlefield site, and the settlement became the town of Battle. The abbey was destroyed by Henry VIII when he separated the Church of England from Roman Catholic rule.