The quote 'What have I done?' is the tragic final line of Colonel Nicholson in 'The Bridge on the River Kwai.' However, the film's most famous musical moment is the 'Colonel Bogey March,' whistled by the POWs. To support this on-set whistling, the score featured the piccolo. The piccolo is a half-size flute and the highest-pitched instrument in the orchestra. Its bright, piercing sound captured the 'stiff upper lip' defiance of the British soldiers. The contrast between the jaunty piccolo march and the film's dark ending became a cinematic legend. This choice proved that even the smallest instrument can carry the pride and tragedy of a movie legend and the weight of its military dialogue.