(Al Jazeera/AFP) – Boko Haram members have destroyed an estimated 1,100 schools this year in their stronghold region surrounding Lake Chad, the United Nations envoy to the area said Monday. The targeted schools were in Cameroon, Chad, Niger and Nigeria, the four countries most affected by the armed uprising, said Toby Lanzer, who became U.N. envoy to central Africa’s restive Sahel region in July.