Following the Second World War, the U.S. helped form the North Atlantic Treaty Organization in 1949 to resist communist expansion and supported resistance movements and dissidents in the communist regimes of Central and Eastern Europe and the Soviet Union during a period known as the Cold War. One example is the counterespionage operations following the discovery of the Farewell Dossier which some argue contributed to the fall of the Soviet regime.[25][26] After Joseph Stalin instituted the Berlin Blockade,[27] the United States, Britain, France, Canada, Australia, New Zealand and several other countries began the massive "Berlin airlift", supplying West Berlin with up to 4,700 tons of daily necessities.[28] U.S. Air Force pilot Gail Halvorsen created "Operation Vittles", which supplied candy to German children.[29] In May 1949, Stalin backed down and lifted the blockade.[30][31] The U.S. spent billions to rebuild Europe and aid global development through programs such as the Marshall Plan.