If you ever wondered what the biggest selling single of all time is, the answer may surprise you. 'White Christmas', by Bing Crosby has sold over 50 million copies since its release in 1942. Following is Elton John’s 1997 version of 'Candle in the Wind', and 'In the Summertime' by Mungo Jerry. The most streamed song? 'Blinding Lights' by The Weekend with 5.3 Billion streams.