What separates hip hop dance from other forms of dance is that it is often improvisational (freestyle) in nature and hip hop dancers frequently engage in battles—formal or informal one on one dance competitions. Freestyle sessions and battles are usually performed in a cipher, a circular dance space which forms naturally once the dancing begins. It was DJ Afrika Bambaataa that outlined the five pillars of hip hop culture including breaking as one of them (along with rapping, DJing, beatboxing, and graffiti).
The dance industry responded to hip hop dance by creating a more commercial version of it. This "studio hip hop", sometimes called new style is the kind of hip hop dancing seen in most rap and R&Bmusic videos. Technically speaking, hip hop dance (new style hip hop that is) is characterized as hard hitting. The feet are grounded, the chest is down, and the body is kept loose so that a dancer can easily alternate between hitting the beat or riding through the beat. This is in contrast to ballet or ballroom dancing where the chest is upright and the body is stiff. In addition, new style hip hop is very rhythmic and there's a lot of emphasis placed on musicality—how sensitive your movements are to the music.
In ballet, a pas de deux is a dance duet in which two dancers, typically a male and a female, perform ballet steps together. It usually has five parts, consisting of an entrée (introduction), an adagio, two variations (a solo for each dancer), and a coda (finale). The pas de deux is characteristic of classical ballet and can be found in many well-known ballets. It is often considered to be the bravura highlight of a ballet and is usually performed by a leading pair of principal dancers.
Marius Petipa (born Victor Marius Alphonse Petipa on 11 March 1818 in Marseille, Kingdom of France) was a ballet dancer, teacher, and choreographer. His mother was an actress and drama teacher, while his father was a ballet master and teacher.
Petipa is noted for his long career as Premier Maître de Ballet of the St. Petersburg Imperial Theatres, a position he held from 1871 until 1903. He created over fifty ballets, some of which have survived in versions either faithful to, inspired by, or reconstructed from the original: The Pharaoh's Daughter (1862); Don Quixote (1869); La Bayadère (1877); Le Talisman (1889); The Sleeping Beauty (1890); etc.