brigades and 6 military regions. Modern infantry have diverse capabilities and this is reflected in the varied roles assigned to them. There are four operational roles that infantry battalions can fulfil: air assault, armoured infantry, mechanised infantry, and light role infantry. Navy Under the command of the Spanish Admiral Chief of Naval Staff, stationed in Madrid, the Spanish Navy has four area commands: Cantabrian Maritime Zone with its headquarters at Ferrol on the Atlantic coast Straits Maritime Zone with its headquarters at San Fernando near Cadiz Mediterranean Maritime Zone with its headquarters at Cartagena Canary Islands Maritime Zone with its headquarters at Las Palmas de Gran Canaria. The current flagship of the Spanish Navy is the amphibious assault ship/aircraft carrier . In addition, the fleet consists of: 2 amphibious transport docks, 11 frigates, 3 submarines, 6 mine countermeasure vessels, 23 patrol vessels and a number of auxiliary ships. The total displacement of the Spanish Navy is approximately 220,000 tonnes. As of 2012, the Armada has a strength of 20,838 personnel. Marines The Marines, in Spanish, Infanteria de Marina, are the marine infantry of the Spanish Navy, the oldest in the world. It has a strength of 5,000 troops divided into base defense forces and landing forces. One of the three base defense battalions is stationed with each of the Navy headquarters. "Groups" (midway between battalions and regiments) are stationed in Madrid and Las Palmas de Gran Canaria. The Tercio (fleet — regiment equivalent) is available for immediate embarkation and based out of San Fernando. Its principal weapons include light tanks, armored combat vehicles, self-propelled artillery, and SPIKE antitank missiles. Air and Space Force Spanish Air and Space Force currently has 10 fighter squadrons, each with 18-24 airplanes. The Air and Space Force also has 15 operational air bases around the country. The Air and Space Force operates a wide-ranging fleet of aircraft, from fighters to transport aircraft and passenger transports to helicopters. It maintains some 450 aircraft in total, of which around 130 are fighter aircraft (Eurofighter Typhoons and F-18 MLU). The Spanish Air and Space Force is replacing older aircraft in the inventory with newer ones including the recently introduced Eurofighter Typhoon and the Airbus A400M Atlas airlifter. Both are manufactured with Spanish participation; EADS CASA makes the Eurofighter's right wing and leading edge slats, and participates in the testing and assembly of the airlifter. Its aerobatic display team