Short answers, pulled from the story.
Heavy metal music originated in 1968 when three British bands named Led Zeppelin, Black Sabbath, and Deep Purple formed to create a new genre. Blue Cheer released their debut album Vincebus Eruptum in January 1968 featuring what many consider the first true heavy metal recording.
Heavy metal is traditionally characterized by loud distorted guitars, emphatic rhythms, dense bass-and-drum sound, and vigorous vocals. The electric guitar projects sonic power through amplification while Marshall Amps are frequently used to achieve the specific texture required for the style.
During the 1980s the Parents Music Resource Center petitioned U.S. Congress to regulate the industry due to objectionable lyrics leading to lawsuits against artists like Ozzy Osbourne and Judas Priest. In 1997 Egyptian police jailed young fans accused of devil worship after finding recordings during home searches and Malaysia banned Lamb of God from performing there in 2013 on grounds that lyrics could be interpreted as religiously insensitive.
Down-the-back long hair became the most crucial distinguishing feature of metal fashion originally adopted from hippie subculture before symbolizing hate and angst by the 1980s and 1990s. Performers typically wore light-colored ripped jeans black T-shirts boots and black leather or denim jackets while bands like Kiss performed with white and black face makeup and spiked clothing.
Many subgenres developed outside the commercial mainstream during the 1980s such as crossover thrash including categories mapped by editors of AllMusic and critic Garry Sharpe-Young. Punk rock emerged in the mid-1970s as a reaction against overindulgent rock music while Motörhead founded in 1975 became the first important band to straddle the punk-metal divide.