Metallica‘s 1991 self-titled album has become the fourth studio release ever to reach a historic chart record. The album, affectionately known as The Black Album, has officially spent a total of 750 weeks on the Billboard 200. It’s the fourth record in history to spend that amount of time on the chart, following Pink Floyd‘s The Dark Side of the Moon (1973), the Bob Marley and The Wailers compilation album Legend (1984) and Journey‘s Greatest Hits (1988). Therefore, The Black Album is the youngest album to reach the chart milestone — and is the second studio album to do so, as the Bob Marley a…