Fireworks burst in American skies tonight to celebrate the Fourth of July - other anniversaries include the birth of Louis Armstrong and the start of work on the Panama Canal in 1904. Cliff Michelmore digs into the diaries to consider the people, places and events of 4 July in days gone by - with panellists Peter Purves , Wincey Willis Fred Harris and - keeping it in the family - Jean Metcalfe. Written by ROB METCALFE Producer DIRK MAGGS