article courtesy wikipedia
Ḥusayn ibn ‘Alī ibn Abī Ṭālib (حسين بن علي بن أﺑﻲ طالب) (third of Shaban 4 AH / 8th January 626 AD, at Medina - tenth of Muharram 61 AH / 10th October 680 AD, at Karbala) was the grandson of the Islamic prophet Muhammad and the son of Ali, the first Imam, and the fourth Caliph, and Muhammad's daughter Fatima Zahra. Hussein ibn Ali is revered as a martyr who fought tyranny, as the third Imam by most Shi’a Muslims, and as the second Imam by the majority of Ismaili Shi'a Muslims.
He refused to pledge alligiance to Yazid I, the Umayyad caliph. As a consequence, he was assassinated by Yazid's army in the Battle of Karbala in 680 (61 AH). The anniversary of his martyrdom is called Ashura and it is a day of mourning and religious observance for Shi'a Muslims. Revenge for Husayn's death was turned into a rallying cry that helped undermine the Umayyad caliphate and gave impetus to the rise of a powerful Shia movement.
At the Battle of Karbala it is recorded that seventy two people were martyred. On his way toward Kufa, Husayn encountered the army of Ubayd-Allah ibn Ziyad, the governor of Kufa, which was led by Hurr. When he clashed with them he quoted:
"... Don't you see that the truth is not put into action and the false is not prohibited? The believer has got to be fond of meeting his God justly. So I do not consider the death but blessedness and living with the oppressors other than abjectness."
Part of his speech on Ashura:
"... Lo and behold; an ignoble (i.e ibn Ziyad), son of other ignoble (i.e. Ziyad ibn Abihi), has entangled me in a bifurcation, between either unsheathing the swords or accepting abjectness. And far be it that we accept abjectness. Allah abominates that for us, plus his prophet, believers, the chaste pure gentlewomen, those who do not accept oppression as well as the souls who do not submit to meanness abominate it. They disapprove that we prefer obedience of scrooges to the best sites of murder. Beware; I assault you together with this family while they are few and when the helpers deserted. ... "
On October 10 680(Muharram 10, 61 AH), he and his small group of companions and family members, who were between 108 and 136 men of Husayn ibn Ali (the grandson of Muhammad). , fought with a large army of perhaps 4,000 men under the command of Umar ibn Sa'ad, son of the founder of Kufah. Husayn and all of his men were killed. The bodies of the dead, including that of Husayn, were then mutilated.
Today, the death of Hussein ibn Ali is commemorated during every Muharram, with the most important of these days being its tenth day, Ashura.
Husayn's body is said to have been buried in Karbala, near the site of his death. Most accounts say that his head was later retrieved and interred with his body. The Imam Hussein Shrine was later built over his grave; it is now a holy site of pilgrimage for Shia Muslims.
 Commemoration of Hussein ibn Ali
Main article: Commemoration of Husayn ibn Ali
Husayn's body is said to have been buried in Karbala, near the site of his death. The Imam Hussein Shrine was later built over his grave; it is now a holy site of pilgrimage for all Muslims.
 Shi'a views of Hussein
Shi'ahs regard Hussein as an Imam (lord of the spiritual kingdom) and a martyr.He is believed to be the third imam. He set out on his path in order to save Islam and the Ummah from annihilation at the hands of Yazid. According to Shi'a belief he was a willing sacrifice to religious necessity, and Shi'as view Hussein as an exemplar of courage and resistance against tyranny. Ashura, a day of mourning and self-reflection, is held in honor of his suffering.
As a reward for Hussein's suffering, he will be allowed to intercede for the faithful on the day of judgment.
The saying, "Every day is Ashura, every land is Karbala," is a reminder to live one's life as Hussein did on Ashura, with total sacrifice to Allah and for others. This saying also signifies "We must always remember, because there is suffering everywhere".