Commonly known as "The Black Album," Metallica's self-titled 1991 release marked a significant shift in the band's sound towards a more refined and accessible style. With hits like "Enter Sandman," "Nothing Else Matters," and "The Unforgiven," the album achieved massive commercial success. Its polished production, memorable riffs, and powerful lyrics broadened Metallica's audience, solidifying their status as one of the most influential metal bands of all time. The album remains a staple in rock music, celebrated for its impact and enduring appeal.