Often confused with '80s hair metal (at least by American listeners), glam rock was an almost entirely British phenomenon that became wildly popular during the first half of the '70s. Glam rock was fairly simple, crunchy guitar rock put across with outrageous theatricality. Most of the music was unabashedly catchy, with melodies drawn from teenage bubblegum pop and hip-shaking rhythms from early rock & roll. But those innocent-sounding influences were belied by the delivery, which was all campy, glitzy showmanship and sexuality. In fact, one of the main reasons glam never caught on in the U.S. was that glam artists intentionally played around with gender conventions, dressing themselves up in outlandish, androgynous costumes and makeup. In general, glam rock fell into two schools. The most prevalent one was the intentionally disposable trashiness of T. Rex; leader Marc Bolan pioneered glam's fashion sense and crafted music that was all sexy, silly fun -- or, to put it another way, music where the surface was the substance. Artists like Gary Glitter, Sweet, and Slade followed the T. Rex aesthetic, in the process creating a substyle known as glitter (which was even more exclusively British). But for a style which relied so heavily on image, glam had a surprisingly arty side too, epitomized by David Bowie and Roxy Music. This school was more grandly dramatic and ambitious, both sonically and lyrically; glam was an opportunity for these artists to manipulate their personas at will, making their senses of style part of the overall artistic statement, and exploring the darkness lurking under the music's stylish, glitzy surface. Apart from them, the lone American glam-rock band was the New York Dolls, whose raw, Stonesy proto-punk sounded different from their British peers, but whose trashy aesthetic and transvestite wardrobe clearly put them in the same camp. Glam effectively began with T. Rex's 1971 hit Electric Warrior, but 1972 was its real breakthrough year: T. Rex consolidated its popularity with The Slider; David Bowie released his classic Ziggy Stardust and produced Mott the Hoople's star-making All the Young Dudes album; Roxy Music issued their groundbreaking debut; and the New York Dolls embarked on their first tour of England. Glam rock's creative peak was over by 1975, as most of its remaining major artists were either moving away from the style or releasing subpar work. However, glam had a definite influence on the kids who grew up to head the British punk movement, and an even bigger impact on the theatrical gloom of post-punk. And, of course, glam rock was extremely important to '80s pop-metal, though apart from Def Leppard, many of those bands were American and had minimal knowledge of the original sources.