A Sunni means the one who follows the Sunnah (custom) of Prophet Mohammad (PBUH). Most of the Islamic countries have a majority of Sunni population. According to their faith, Prophet (PBUH) never designated a successor; therefore, the Muslims had the right to choose their Caliph according to the will of the majority. Sunnis give equal respect to the first four Caliphs of Islam, Abu Bakar (R.A), Umar Ibn e Khatab (R.A), Osman (R.A) and Ali (R.A).
These four are also known as Pious Caliphs. The Sunnis believe that the Caliphate cannot be restricted to the family of the Prophet (PBUH) alone and a Caliph must be chosen on sheer merit. Sunnis claim that there were no major differences between Ali (R.A) and the other Pious Caliphates and the history has been distorted by Shiites.
There are some other sub-sects of Sunnis, which differ from each other in a number of laws and religious practices. As per the Sunnis, Imam Mahdi (the anti-Christ) will come in the future. Makkah, Madina and Jerusalem are considered to be the holy cities of this sect.
Shiite means ‘partisan’ or ‘party’ of Ali (R.A). The roots of this sect go back to the time of Prophet’s (PBUH) but it grew stronger only after the tragic incident of Karbala, where Hussain (R.A), a son of Ali (R.A), and his family were martyred by Yazid, the Caliph of that time. Most of the Shiites reside in Iran, Iraq and Yemen. However, they are in minority in a number of other countries. As per this sect, Imam Mahdi is present in the world and will disclose his identity at the right time.