What makes Enter Sandman by Metallica notable?

'Enter Sandman' became one of Metallica's most recognizable tracks, reaching No. 16 on the Billboard Hot 100 and receiving extensive radio airplay. The song's success contributed to the 'Black Album' selling over 16 million copies in the U.S. alone, cementing Metallica's influence on the heavy metal genre and popular music at large. By 1991, Metallica had solidified their status as leaders in the heavy metal scene with their self-titled 'Black Album' following the commercial success of '...And Justice for All.' 'Enter Sandman' marked a pivotal moment, showcasing a more polished sound while retaining their thrash roots, which helped them reach a wider audience and mainstream radio play.