In the early 1960s, the Nashville sound began to be challenged by the rival Bakersfield sound. Nashville's pop song structure became more pronounced, and it morphed into countrypolitan. Countrypolitan was aimed straight at mainstream markets, and it sold well throughout the later 1960s and 1970s. The Bakersfield sound and, later, outlaw country dominated country music among afficianados while countrypolitan reigned on the pop charts.