What is Belly dance?
Belly dance, also known as Raq Sharqi 'Dance of the Orient', has middle eastern roots. The styles and costumes of belly dance vary from place to place within the Middle East and across the world. In the more recent years, several new styles have evolved in the West.
Although they have their differences in style and costuming, they continue to share most of the original characteristics that help distinguish belly dance from other dance forms. Isolations, execution of individual or layered movements, shimmies, undulations, and snake arms are among the most recognizable belly dance moves.
For the World Bellydance Day international routines we have chosen to include three different styles within the same choreography: Cabaret, ATS (American Tribal Style) and Tribal Fusion. These new styles have become popular on a worldwide scale.
About the Styles of the Routine
Cabaret is the westernized version of this middle eastern dance art form and it developed from the film industry. It often blends and incorporates moves from different parts of the MiddleEast into the same dance, i.e. Egyptian and Turkish. This style also has other influences such as jazz and ballet. Costumes are typically very glitzy and decorated with swarovski crystals, glass beads and shiny sequences.
American Tribal Style Belly Dance
Also known as ATS, is a newer style of bellydance created by Carolena Nericcio. American Tribal Style Belly Dance is clearly defined and generally performed in a group, the primary characteristic being that of group improvisation.
The style is also characterized by costumes derived from many "folkloric" and various traditional tribal costuming resources. 
Tribal Fusion is a form of bellydance that began in America in 2000 that stems from ATS. Tribal Fusion was largely popularized by Rachel Brice.  This style is performed to non traditional music. Popping and locking are typical moves incorporated into this style.