Hardcore, punk, and garage rock were the roots of "alternative rock", a diverse grouping of rock subgenres that were explicitly opposed to mainstream music, and that arose from the punk and post-punk styles. In the United States, many cities developed local alternative rock scenes, including Minneapolis and Seattle. Seattle's local scene produced grunge music, a dark and brooding style inspired by hardcore, psychedelia, and alternative rock. With the addition of a more melodic element to the sound of bands like Nirvana, Pearl Jam, Soundgarden, and Alice in Chains, grunge became wildly popular across the United States in 1991. Three years later, bands like Green Day, The Offspring, Rancid, Bad Religion, and NOFX hit the mainstream (with their respective then-new albums "Dookie", "Smash", "Let's Go", "Stranger than Fiction" and "Punk in Drublic") and brought the California punk scene exposure worldwide.