Holiest sites in Shia Islam in the context of "Imam Husayn Shrine"

Shia Islam is the second-largest branch of Islam. It holds that Muhammad designated Ali ibn Abi Talib (r. 656–661) as both his political successor (caliph) and as the spiritual leader of the Muslim community (imam). However, his right is understood to have been usurped by a number of Muhammad's companions at the meeting of Saqifa, during which they appointed Abu Bakr (r. 632–634) as caliph instead. As such, Sunni Muslims believe Abu Bakr, Umar (r. 634–644), Uthman (r. 644–656) and Ali to be 'rightly-guided caliphs', whereas Shia Muslims regard only Ali as the legitimate successor.

Shia Muslims believe that the imamate continued through Ali's sons, Hasan and Husayn, after which various Shia branches developed and recognized different imams. They revere the ahl al-bayt, the family of Muhammad, maintaining that they possess divine knowledge. Shia holy sites include the shrine of Ali in Najaf, the shrine of Husayn in Karbala, and other mausoleums of the ahl al-bayt. Later events, such as Husayn's martyrdom in the Battle of Karbala (680 CE), further influenced the development of Shia Islam, contributing to the formation of a distinct religious sect with its own rituals and shared collective memory.

The holiest sites in Islam are located in the Middle East. While the significance of most places typically varies depending on the Islamic sect, there is a consensus across all mainstream branches of the religion that affirms three cities as having the highest degree of holiness, in descending order: Mecca, Medina, and Jerusalem. Mecca's Al-Masjid al-Haram (including the Kaaba), Al-Masjid an-Nabawi in Medina, and Jerusalem's Al-Aqsa Mosque are all revered by Muslims as sites of great importance.

After the consensus on the first three sites as well as further sites associated with the family of Muhammad, there is a divergence between Sunni Muslims and Shia Muslims on the designation of additional holy sites. Even within each sect, there are disputes as to whether any uniquely holy cities exist apart from the aforementioned three. For Sunnis that argue that there are, sites associated with the Rashidun, other Companions of Muhammad, and Biblical prophets often hold a high level of significance (see holiest sites in Sunni Islam). In particular, the Umayyad Mosque in the city of Damascus and the Ibrahimi Mosque in the city of Hebron have held interchangeable significance as the fourth and fifth-holiest Islamic sites, respectively, for many Sunni Muslims. For Shias, sites associated with the Imamah hold a high level of significance (see holiest sites in Shia Islam).