World's quietest submarine, cruise missiles and smart bombs: The deadly arsenal Putin is using to pound Syria as Russia's awesome firepower drives Isis out of Palmyra Syrian government forces backed by heavy Russian air support have driven Islamic State out of ancient city of Palmyra Assad supported by Putin has inflicted what the army called a 'mortal blow' to militants who seized the city last year and dynamited its ancient temples Putin is using Syria as a testing ground for a terrifying new generation of weapons His warplanes, missiles and tanks, smart bombs and satellite technology have already changed the...