On May 7th 1915, the British trans-Atlantic liner Lusitania was torpedoed by a German submarine. The Germans claimed that the ship was transporting weapons. The Americans denied it and used the disaster to justify their declaration of war.
6th June 1944. The beaches of Normandy are the scene of the most spectacular military operation of all time: the Normandy Landings. They owe their success, though, to a gigantic lie: a phantom army and a network of double agents.
Apr 1994: "Nicotine isn't addictive", the tobacco industry leaders pronounced in front of the US Congress. 4 years later, they had to pay a $200 billion fine and open their archives that uncovered a large-scale strategy of disinformation.
G. W. Bush assured the UN Security Council that Iraq was in possession of weapons of mass destruction and posed a threat to the US, particularly through its links with Al Qaeda. However, it was all untrue.