U.S. Army Lt. Col. Carleton Lee, U.S. European Command exercise director receives the report of nearly 40 nations participating in exercise Combined Endeavor 2013, Sept. 12, 2013. Combined Endeavor, a U.S. European Command-sponsored event, explores and resolves multinational tactics, techniques and procedures and builds command, control, communications and computers (C4) planning experience and knowledge among participating nations.