Christian rock (occasionally abbreviate CR) is a form of rock music played by bands whose members are Christians and who often focus the lyrics on matters concerned with the concept of the Christian faith. The extent to which their lyrics are explicitly Christian varies between bands. Much Christian rock has ties to the Contemporary Christian Music (CCM) scene, while other bands are independent.The Christian rock genre is most popular in the United States, although some Christian bands have worldwide popularity. Related subgenres of Christian music include Christian alternative rock, Christian metal, Contemporary Christian Music, Christian punk, Christian hardcore.