Sea was based on a bestselling novel, in this case the former naval commander Nicholas Monsarrat's story of the battle of the Atlantic. Others, like The Dam Busters (1954), with its exciting tale of the inventor Barnes Wallis's unorthodox bouncing bomb and its distinctive theme music, were true stories. The Dam Busters became the most popular film in Britain in 1955, and remained a favourite as of 2015 with a 100% score on Rotten Tomatoes, though, partly because it celebrated an "exclusively British [victory]", it failed in the American market. A large number of war films were made in the 1955–1958 period in particular. In 1957 alone, Bitter Victory, Count Five and Die, The Enemy Below, Ill Met by Moonlight, Men in War, The One That Got Away, and Seven Thunders, and the highly successful, critically acclaimed pictures The Bridge on the River Kwai (which won the Academy Award for Best Picture that year) and Paths of Glory were released. Some, such as Bitter Victory, focused more on the psychological battle between officers and egotism rather than events during the war. The Bridge on the River Kwai brought a new complexity to the war picture, with a sense of moral uncertainty surrounding war. By the end of the decade the "sense of shared achievement" which had been common in war films "began to evaporate", according to Pulver. Hollywood films in the 1950s and 1960s could display spectacular heroics or self-sacrifice, as in the popular Sands of Iwo Jima (1949) starring John Wayne. U.S. Marines considered Sands of Iwo Jima visually authentic, but found Lewis Milestone's Battle Cry (1955), with its attention to the lives of the men, the more realistic film. The formula for a successful war film consisted, according to Lawrence Suid, of a small group of ethnically diverse men; an unreasonable senior officer; cowards became heroic, or died. Jeanine Basinger suggests that a traditional war film should have a hero, a group, and an objective, and that the group should contain "an Italian, a Jew, a cynical complainer from Brooklyn, a sharpshooter from the mountains, a midwesterner (nicknamed by his state, 'Iowa' or 'Dakota'), and a character who must be initiated in some way". Films based on real commando missions, like The Gift Horse (1952) based on the St. Nazaire Raid, and Ill Met by Moonlight (1956) based on the capture of the German commander of Crete, inspired