Al-Shabab
The regional havoc caused by the al-Qaeda-affiliated militia in the Horn of Africa only grew in 2011. Somalia's fledgling, fragile transitional government in Mogadishu claimed victory over al-Shabab fighters warring in the capital in August, a premature declaration that was soon followed by a slew of deadly bombings and attacks. As a U.N.-declared famine sent hundreds of thousands in southern Somalia — a region dominated by the Islamist militia — fleeing to refugee camps on the Kenyan border, aid groups complained that al-Shabab was obstructing aid to millions facing malnutrition. And the Kenyan government had its own bone to pick: in response to al-Shabab bomb attacks in Nairobi and the group's incursions across the border and kidnapping of foreign tourists in Kenya, the country's military launched its own offensive against al-Shabab, a quiet war that may rage on into 2012.