Further information: black metal The first wave of black metal emerged in Europe in the early and mid-1980s, led by the United Kingdom's Venom, Denmark's Mercyful Fate, Switzerland's Hellhammer and Celtic Frost, and Sweden's Bathory. By the late 1980s, Norwegian bands such as Mayhem and Burzum were heading a second wave.[227] Black metal varies considerably in style and production quality, although most bands emphasize shrieked and growled vocals, highly distorted guitars frequently played with rapid tremolo picking, a dark atmosphere[224] and intentionally lo-fi production, with ambient noise and background hiss.[228]