FTP, name this branch of Islam, opposed to Sunnites.
This religious grouping currently has between 60 and 80 million adherents.  Among its holy sites is that of the Battle of Karbala near Kufa in modern Iraq, the site of a 680 battle, which saw the defeat of the forces of Hussein by those loyal to the caliph.  Hussein was the son of the 4th caliph, Ali, and the adherents of this sect believe the succession of caliphs should have been through Ali's line.  FTP, name this branch of Islam, opposed to Sunnites.
This religious grouping currently has between 60 and 80 million adherents.  
Shi'a  or Shi'ites