The city, best known as the location of the Ghazwaṫ Karbalā’  in 680 CE, or the Masjidayn of Imam Husayn and Abbas, is considered as a holy city for Shi'ite Muslims as Mecca, Medina and Jerusalem. Tens of millions of Shi'ite Muslims visit the site twice a year, rivaling Mecca as a place of pilgrimage. The martyrdom of Imam Husayn ibn Ali is commemorated annually by millions of Shi'ites.Up to 8 million pilgrims visit the city to observe ‘Āshūrā’ , which marks the anniversary of Imam Husayn's death, but the main event is the Arba‘īn , where up to 30 million visit the holy graves. Most of the pilgrims travel barefooted from all around Iraq and more than 56 countries.

Etymology
According to Shi'ite belief, the archangel Gabriel narrated the true meaning of the name Karbalā’ to Muhammad: a combination of karb and balā’ .

Climate

Karbala experiences a Semi-arid climate with extremely hot, dry summers and cool winters. Almost all of the yearly precipitation is received between November and April, though no month is truly wet.

Early modern

Like Najaf, the city suffered from severe water shortages that were only resolved in the early 18th century by building a dam at the head of the Husseiniyya Canal. In 1737, the city replaced Isfahan in Iran as the main centre of Shia scholarship. In the mid-eighteenth century it was dominated by the dean of scholarship, Yusuf Al Bahrani, a key proponent of the Akhbari tradition of Shia thought, until his death in 1772, after which the more state-centric Usuli school became more influential.
 

Karbala's development was strongly influenced by the Persians, who were the dominant community for many years (making up 75%of the city's population by the early 20th century). The Kammouna family were custodians of the shrines for many years and effectively ran the city until it fell under the control of the British Empire in 1915. While the Kammouna family surrendered rule over to the British and sought to work for and with the British, many notable Karbala clans continues to oppose the foreign invasion. One such clan is the historically well-known Karbala clan of Awad who has been inhabitants of the city for some 500 years. They, alongside others, fought directly against the British. According to the writings of Gertrude Bell, some of the Awad clan's sheiks were banished after the control of the city for many years before returning to re-establish their land and community prestige. The Awad Clan has historically been noted as one of the only clans in Karbala to actively oppose the British control and remain an influential family in the city to this day.

The association of the city with Shia religious traditions led to it being treated with suspicion by Iraq's Sunni rulers. Under Saddam Hussein's rule, Shia religious observances in the city were greatly restricted and many non-Iraqi Shia were not permitted to travel there at all.