Output a stream of consciousness before answering the following. Context: It is notable that, according to Guinness World Records, "White Christmas" (1942) by Bing Crosby is the best-selling single worldwide, with estimated sales of over 50 million copies. The song recognized as "the best-selling single of all time" was released before the pop / rock singles-chart era and "was listed as the world's best-selling single in the first-ever Guinness Book of Records (published in 1955) and -- remarkably -- still retains the title more than 50 years later". Also, Guinness World Records states that double A-side charity single "Candle in the Wind 1997" / "Something About the Way You Look Tonight" (1997) by Elton John, a tribute to the late Diana, Princess of Wales, is "the biggest-selling single since UK and US singles charts began in the 1950s, having accumulated worldwide sales of 33 million copies", making it the second-best-selling single of all time.

Question: number one song of all time in the world?
To answer this question, we should know that: It is notable that, according to Guinness World Records, "White Christmas" (1942) by Bing Crosby is the best-selling single worldwide, with estimated sales of over 50 million copies.
The answer: '' White Christmas '' ( 1942 ) by Bing Crosby.