The can-can (also spelled cancan or Can Can) is regarded today primarily as a physically demanding music hall dance, performed by a chorus line of female dancers who wear costumes with long skirts, petticoats, and black stockings, harking back to the fashions of the 1890s. The main features of the dance are the lifting up and manipulation of the skirts, with high kicking and suggestive, provocative body movements.
The cancan is danced in 2/4 time, and is now usually performed on stage in chorus-line style. In France in the 19th century the cancan remained a dance for individual entertainers, who performed on a dance floor. In the United Kingdom, the United States and elsewhere, the cancan achieved popularity in music halls, where it was danced by groups of women in choreographed routines. This style was imported into France in the 1920s for the benefit of tourists, and the French Cancan was born—a highly choreographed routine lasting ten minutes or more, with the opportunity for individuals to display their "specialities". The main moves are the high kick or battement, the rond de jambe (quick rotary movement of lower leg with knee raised and skirt held up), the port d'armes (turning on one leg, while grasping the other leg by the ankle and holding it almost vertical), the cartwheel and the grand écart (the flying or jump splits). Additionally, performance practice of the can-can almost always includes the dancers screaming, yelling, cat-calling and trilling while dancing.
Although the dance is now considered a part of world culture, and the main feature observed today is how physically demanding and tiring the dance is to perform; by the late 1860s, it was considered extremely inappropriate[1], and in the early 20th century downright erotic[2]. When the dance initiated in the late 19th century, it was considered little more than a scandalous thing for youngsters, similar to how rock and roll would be perceived later on.
Reference:
[1], [2]