Jamaican R&B artists developed their nation's first indigenous music genre when they began to incorporate jazz, African and Calypso rhythms into their songs in the late 1950s. The result was Ska, a fusion of the unique Jamaican mento rhythms with R&B. In Ska, the drum comes in on the 2nd and 4th beats, while the guitar emphasizes the 2nd, 3rd, and 4th beats. Ska bands usually consist of a strong rhythm section, guitars, keyboards and brass. The early Ska music of in the '60s and '70s spawned later revivals. The first was in the U.K. in the '80s, giving rise to bands like Madness and the Specials. The next, known as Third Wave Ska, struck the U.S. in the '90s.