Metallica is one of my favorite older bands! 
Same here. The black album played a big part in my formative years
What was their most popular song do you know?
I think Enter Sandman. They we great early heavy metal
I love Enter Sandman! The Unforgiven is another favorite of mine.
Enter Sandman was the first single from their self-title album in 1991. So long ago.
Wow that was a long time ago! 3 years after I was born! 
That song actually went platinum with over a millions copies sold
That is amazing. Metallica will always be a classic band in my opinion.
Metallica
Metallica is an American heavy metal band. The band was formed in 1981 in Los Angeles, California, by drummer Lars Ulrich and vocalist/guitarist James Hetfield, and has been based in San Francisco, California for most of its career. The group's fast tempos, instrumentals and aggressive musicianship made them one of the founding "big four" bands of thrash metal, alongside Megadeth, Anthrax and Slayer. Metallica's current lineup comprises founding members Hetfield and Ulrich, longtime lead guitarist Kirk Hammett and bassist Robert Trujillo
child, and has said they were the reason he wanted to play guitar.
He was also a fan of 70s & 80s hard rock and heavy metal bands, including White Lion, AC/DC, Iron Maiden, Queen, Black Sabbath, Deep Purple and Bon Jovi.
Masterpiece occasionally played cover songs by these bands, including Queen's "I want to break free", Bon Jovi's "It's my life," and Metallica' "Enter Sandman".
He has also cited Led Zeppelin