Atlanta-bred rapper Lil Jon first came on the scene as a DJ at Atlanta night clubs. In 1993, he signed on as a producer for Jermaine Dupri's So So Def label. The artist, born Jonathan Smith, soon formed his own group, Lil Jon & the East Side Boyz, featuring Big Sam and Lil Bo. Through the years, Lil Jon has continued to produce hits for other artists. He has put out mixed tapes and released a solo debut in 2010.
Atlanta: LudacrisLudacris was born Christopher Brian Bridges in Chicago and moved to Atlanta when he was 9-years-old. He started rapping at a young age and after graduating from high school, Ludacris attended Georgia State University as a music management student from 1998-1999. The three-time Grammy-winning artist released his debut album in 2000.
Atlanta: UsherBorn in Dallas, R&B singer Usher moved with his family to Atlanta when he was 12. It was there that he emerged as a budding star, winning best teen male vocalist on "Star Search." In 1994, he released his self-titled debut album. He has gone on to release several albums and has won seven Grammys.
Atlanta: B.o.BRapper and producer B.o.B (real name Bobby Ray Simmons, Jr.) was born in Winston-Salem, N.C., but spent his high school years right outside Atlanta, in Decatur, Ga. The Grammy-nominated artist was one of the many rappers to come out of Atlanta in the 2000s, singing his first major label record deal when he was 17.
Atlanta: OutKastOutKast's Andre 3000 and Big Boi met in 10th grade at Tri-Cities High School in Atlanta. The hip hop duo signed to LaFace Records in 1992 and released its debut album two years later. Hits soon followed with "Ms. Jackson," "Hey Ya!" and "The Way You Move."
Oslo: A-HaResearchers named Oslo, Norway, the overall music leader in Western Europe, beating out London and Paris.
Probably one of the most well-known groups to come out of Oslo is A-ha, the pop band behind the '80s hit, "Take On Me." Featuring Morten Harket Magne Furuholmen and Pal Waaktaar, A-Ha has gone on to release several albums and toured as recently as 2010.
Oslo is home to heavy metal acts, indie rock bands and jazz acts.
Stockholm: Lykke LiSweden's capital followed Oslo as one of the leaders in All Music category for Western Europe.
Swedish singer-songwriter Lykke Li grew up in Stockholm before moving with her family to Portugal. She had success with the 2007 EP "Little Bit" and followed that up with her debut full-length album, "Youth Novels."
Montreal: Arcade FireMontreal was labeled the top leader of indie music.
Arcade Fire, pictured here, hails from the Canadian city. The band first came on the scene in 2004 with its breakthrough album "Funeral." Rolling Stone named it the No. 1 album of the '00s. The group's most recent album, "The Suburbs," won the 2011 album of the year Grammy. The city is bursting with indie rock and folk groups.
Montreal: Land of TalkElizabeth Powell of Land of Talk performs at Central Park Summer Stage July 16, 2007, in New York.
The Montreal-based singer has been making music since the age of 14. The group's first studio album, "Some of Lakes," came out in 2008.
Montreal: ChromeoElectrofunk duo Chromeo consists of Patrick Gemayel (P-Thugg) and David Macklovitch (Dave 1). They met in the mid-1990s at College Stanislas in Montreal. Chromeo released its debut album, "She's in Control," in 2004.
Montreal: Sam RobertsMontreal-based singer-songwriter Sam Roberts is seen here performing as part of the Austin City Limits Music Festival on Sept. 17, 2006.
Roberts grew up in Montreal and attended McGill University there. The Juno Award-winning rocker released his first album in 2000 and has been playing music ever since.