The Japanese garrison in Mandalay chose not to surrender, using the forts built by the British and the maze of pagodas in downtown Mandalay to fight to the death in an urban battle that destroyed much of the city, which finally fell to the British 14th Army on 20 March 1945. Slim's plan was a masterpiece of operational art, and the capture of Meiktila left most of Japan's troops stranded in Burma without supplies. The Allies had reached the open plains of central Burma, sallying out and breaking Japanese attacking forces in isolation, maintaining the initiative at all times, backed up by air-land cooperation, including resupply by air and close air support, performed by both RAF and USAAF units. Slim followed up this victory by ordering his coastal corps to seize the mouth of the Irrawaddy where it flowed into the Bay of Bengal.