I can't be precise but I believe that in the UK, Celine Dion's My Heart Will Go On is the one of the biggest selling songs there.
rodolph the red nosed raindeer . Gene autry
Supermassive Black Hole. Why? Most views on YouTube Most selling single by Muse. A song from the Most selling album by Muse
"Candle in the Wind 1997"
Duncan
Bad Romance is Lady Gaga's biggest selling song she sold over 50 million singles.
J5the biggest rap song ever is coolio gangstar paradise
They biggest selling single is Step by step.
Hallelujah
white Christmas...
kimono
"Candle in the Wind 1997"/"Something About The Way You Look Tonight" in 1997 is Elton John's biggest selling single, and in fact, is the biggest selling single since singles charts began in the 1950s.
"About You Now", The first single of their fifth album, 'Change'. It went number one for 4 weeks, and is the biggest selling sugababes song of all time.
rodolph the red nosed raindeer . Gene autry
Supermassive Black Hole. Why? Most views on YouTube Most selling single by Muse. A song from the Most selling album by Muse
"Candle in the Wind 1997"
the biggest selling song that year was "Physical" by Olivia Newton-John. It was also the biggest selling song of that decade!.
I'm not sure about worldwide sales but the biggest selling UK single is Do They Know It's Christmas by Band Aid.