Progressive rock, often shortened to prog rock, is a genre that emerged in the late 1960s as a fusion of rock and classical music. It is characterized by its complex compositions, extended musical pieces, and eclectic use of instrumentation including synthesizers and orchestral elements. Notable bands of the genre, such as Pink Floyd, Genesis, and Yes, have made significant contributions to music with their conceptual albums and experimental approach. The genre's influence can still be seen today in various sub-genres like neo-progressive rock and progressive metal.