Rumba is a dance style that emerged in the African slave community in Cuba. Some dancers say the Rumba is the most erotic and sensual latin dance, for its relatively slow rhythm and the hip movement.
Rumba is sometimes confused with salsa, with which it shares origins and essential movements. However, rumba's rhythm begins with one beat pause, then three equally long steps. Salsa misses one beat, and counts quick-quick-slow, where slow is a movement as long as both quick steps together.
Rumba is thought to have contributed to the origin of the cha-cha-cha, and indeed most figures (if not all, somehow) can be reinterpreted in cha-cha-cha.