The world’s three most infamous terrorist organizations are working together at Al-Qaeda-run training camps in the Sahara Desert in Mauritania, where dozens of recruits from the U.S., Canada and Europe are being indoctrinated into violent jihad and training for attacks that could expand the so-called caliphate across North and West Africa, according to analysts. ISIS, Boko Haram and Al-Qaeda all have links to two camps in the remote sands of the expansive North African country, according to Veryan Khan, editorial director for the Florida-based Terrorism Research & Analysis Consortium, which tracks international terrorism and had a source on the ground...