In North America and Europe the decade was particularly revolutionary in terms of popular music, as it saw the evolution of rock. At the beginning of the 1960s, pop and rock and roll trends of the 1950s continued; nevertheless, the rock and roll of the decade before started to merge into a more international, eclectic variant. In the early-1960s, rock and roll in its purest form was gradually overtaken by pop rock, beat, psychedelic rock, blues rock, and folk rock, which had grown in popularity. The country- and folk-influenced style associated with the latter half of 1960s rock music spawned a generation of popular singersongwriters who wrote and performed their own work. Towards the decade's end, genres such as Baroque pop, sunshine pop, bubblegum pop, and progressive rock started to grow popular, with the latter two finding greater success in the following decade. Furthermore, the 1960s saw funk and soul music rising in popularity; rhythm and blues in general remained popular. The fusion of R&B, Gospel -and original rock and roll was a success until the mid-part of the decade. Aside from the popularity of rock and R&B music in the 1960s, Latin American as well as Jamaican and Cuban music achieved a degree of popularity throughout the decade, with genres such as Bossa nova, the cha-cha-cha, ska, and calypso being popular. From a classical point of view, the 1960s were also an important decade as they saw the development of electronic, experimental, jazz and contemporary classical music, notably minimalism and free improvisation.