Overview:Love it or hate it, the Eurovision Song Contest has not only redefined Europe, it has redefined music. Conceived in 1956 as a great televised musical event which would bring peace and harmony to Europe, it has since launched meteoric careers and made hits of songs such as Waterloo, Volare and Boom Bang a Bang. It has also bred an annual hotbed of political intrigue, racial rivalry, allegations of bribery and plain old sour grapes. In this programme Abba, Sandie Shaw, Cliff Richard and many others sing while Katie Boyle, Bucks Fizz, John Peel, Michael Ball and Johnny Logan try to explain that special Eurovision "ring-a-ding-ding".