One of the most noticeable effects of Gorbachev’s reforms in the Soviet Union in the 1980s was the emergence from underground of many previously-repressed subcultures, and alongside dissident poetry, modern dance, literary novels, experimental filmmaking and a whole gamut of cultural expression, one of the largest and most powerful cultural forces to be unleashed was metal. The Monsters of Rock festival in Moscow in September 1991 showed how large.
Although estimates vary, most accept that somewhere between 1.4 and 1.6 million people saw AC/DC, Metallica, The Black Crowes, E.S.T. and Pantera at Tushino Airfield, northwest of Moscow city centre; one of the largest concert crowds ever. Combined with a public infrastructure that had almost no experience in dealing with large rock concerts, the day seems to have been a chaotic experience, with crowd control carried out by police and Red Army units (including a helicopter unit) on a crowd who were, in most cases, seeing their first ever rock concert.
One of the persistent rumours about the concert is that Metallica were personally asked to play by Gorbachev. Maybe this was the sort of thing he was into: