Aiden O'brien has 31 Metallica concerts.

Metallica (formed in 1981 in Los Angeles) is widely recognized as one of the most influential heavy metal bands in history, often acknowledged as one of the "Big Four" of thrash metal, alongside Megadeth, Anthrax, and Slayer. Metalica was formed by lead singer James Hetfield and drummer Lars Ulrich with Dave Mustaine joining on lead guitar and Ron McGovney on bass. McGovney departed in 1982 and was replaced by Cliff Burton, who died in 1986 when the band's tour bus crashed in Sweden. Jason Newsted replaced Burton, departing in 2001. Robert Trujillo joined the band in 2003 and remains its longest-lasting bassist to date. Some of Metalica's most popular songs include "One," "Enter Sandman," "Ride the Lightning," "Nothing Else Matters," "Wherever I May Roam," "For Whom the Bell Tolls," "Sad but True," "Unforgiven," "Master of Puppets," which was featured in Netflix's "Stranger Things" Season 4 finale.