In the years leading up to the release of their classic self-titled record in 1991, Metallica achieved massive success on their own terms. 'Enter Sandman' opened the door to something even bigger.

Joining forces with producer Bob Rock for the first time, Metallica's so-called "Black Album" would be the album to truly introduce the band to an international audience.

The opening track and first single from the record, 'Enter Sandman,' which claims the No. 31 position on our Top 100 Classic Rock Songs list, was arguably unlike any other the band had written to date. The record's streamlined -- and some might argue overly accessible -- sound undoubtedly played a big part in the album being such a massive success.

Indeed, Rock was responsible for pushing James Hetfield and company in directions they had not previously traveled. Listening to the ferocity of the band's playing in the song, it is tough to believe that they had any doubt about the path they had chosen. Largely abandoning the thrash-metal roots that had built them such a loyal following, they dared fans to follow along after a pretty big left turn. Everyone had to decide quickly if they were in or out, and fortunately the masses gave a big collective thumbs-up.

'Enter Sandman' was one of five singles released from the record. To this day, almost 21 years later, each of the singles released are among the best received in concert. 'Enter Sandman' would only make it to the No. 16 spot on the Billboardsingles chart. However with more than 15 million copies of the "Black Album" sold in America alone, there is little arguing that, with this song and this album, the group became the bona-fide superstars that they deserved to become.

Skip to: No. 100 | No. 80 | No. 60 | No. 40 | No. 20

Watch Metallica Perform 'Enter Sandman'

More From Ultimate Classic Rock