What better way is there to begin this list than by lauding what many consider to be Metallica's greatest achievement, Master of Puppets (1986)? A true masterpiece from start to finish, it single-handedly led to thrash metal's domination over both the San Francisco Bay Area and the entire world, containing such powerhouse anthems as "Welcome Home (Sanitarium)", "Battery" and, of course, the immense, progressive title track.
However, one evidence of its sheer musical brilliance that a fair few seem to bring up is the ingenious way the record matches its lyrical themes with its music.
For example, the previously mentioned "Welcome Home..." is a track that tackles the concept of insanity and mental institutions head-on in a manner inspired by the book One Flew Over the Cuckoo's Nest. However, the way its music builds and varies, unpredictably switching from clean to heavy and then to full-on aural madness, match the frantic, incalculable nature of the insane mind.
"Disposable Heroes", with its firmly anti-war lyrics, contains pummelling percussion that, at alternate points, resembles either the pounding of war drums or the relentless, noisy chatter of machine gun fire. "Battery", which tackles "assault and battery", relates the danger and suddenness of the emotion of anger by beginning with a tranquil acoustic passage, before descending into one of its parent album's most intense guitar riffs.
The Cthulhu-orientated "The Thing That Should Not Be", meanwhile, possesses slow, sluggish, heavy riffs that mimic the feel of an immense beat dragging itself through the crushing depths.
It is these cues and mastery of tone and aura that elevates Master of Puppets above even other Metallica albums, and is one of the many reasons as to why the album remains a metal classic.