The Dayton Agreement, reached at Wright-Patterson Air Force Base in Ohio, ended the three-and-a-half-year Bosnian War, the bloodiest conflict in Europe since World War II. The war involved ethnic cleansing and massacres, most notably at Srebrenica. Negotiated by U.S. diplomat Richard Holbrooke and leaders from Bosnia, Serbia, and Croatia, the agreement preserved Bosnia and Herzegovina as a single state but divided it into two semi-autonomous entities: the Federation of Bosnia and Herzegovina (mostly Bosniaks and Croats) and the Republika Srpska (mostly Serbs). While the agreement successfully stopped the fighting and provided a framework for reconstruction, it also created a complex and often gridlocked political system that continues to challenge the country's integration into the European Union today.