Conga festivals and congresses

The conga line is a Latin American carnival march that was first developed in Cuba and became popular in the United States in the 1930s and 1950s. The dancers form a long, processing line. It has three shuffle steps on the beat, followed by a kick that is slightly ahead of the fourth beat. The Conga, a term widely believed to be derive from the African region of Congo, is both a lyrical and danceable genre, rooted in the music of carnival troupes or comparsas.

The conga dance was originated by the slave people who were taken from Congo Africa as slaves in Cuba. They started the dance while they were chained together, and has important associations with Afro-Cuban Santeria religion. The Conga dance was not a slave-chain dance, but the dancing and chanting during the Easter when the "Congo’s" during the festivities, followed the processions of the Virgin Mary.

Also the music and dance was performing originally in carnival processions and originating African slave celebrations. The Conga dance was originally a street dance in Cuba.

Source:
http://en.wikipedia.org/wiki/Conga_line