STRONGHOLDS OF THE 10/40 WINDOW This intercessor's guide features maps and information on each nation, covering trends, religions, people groups, and historical background.The 10/40 Window is the primary spiritual battleground in the world today. The very cradle of civilization is now the Church's final evangelistic frontier. The Sentinel Group has produced Strongholds of the 10/40 Window as a handbook for those who are serious about the role of prayer as a tool in global evangelism.