For almost 30 years Belgium's Special Intervention Squadron (ESI) has participated in peacekeeping operations, operated against terrorist and criminal activities, and protected VIP's and citizens. The ESI intervenes in extreme terrorist and criminal attacks involving hijacking and kidnapping (including aircraft, ship, building, bus, and train takeovers); handles high-risk arrests of dangerous terrorists; assists other law enforcement agencies in securing large events of national and international importance; protects Belgian VIP's as well as foreign Presidents and heads-of-state visiting Belgium; and assists prison authorities in dealing with riots and severe disturbances, and transporting and escorting extremely violent prisoners. Candidates for the ESI must be experienced Gendarmerie officers already on active duty. Once selected, candidates go through a 3-month basic training program followed by a 10-month intervention course. The article includes details of the candidate selection process and of the tactical training course, and characteristics of weapons and other equipment used by the ESI.