Determining which song was Elvis’ biggest hit is a tricky ... Now Or Never” — which is believed to be Presley’s biggest ...

In the course of 24 hours, Elvis Presley scored his first No. 1 hit, flopped in Las Vegas, and set off a new wave of rock 'n' roll.

It was a single that I remember ... It's Now Or Never had been the biggest international hit of Elvis Presley's career, eventually selling an astonishing 25 million copies worldwide.