Smart History
Smarthistory: The Kaaba
Smarthistory presents the history and form of the Kaaba and how it has been modified throughout its history up to modern times. With links to additional resources.
Other
Looklex: Mecca
Encyclopedia entry that details the important points and history about the holy city of Mecca and briefly refers to the mosque and the Ka'ba.
Khan Academy
Khan Academy: Hajj: Islamic Middle East
One of the five pillars of Islam central to Muslim belief, Hajj is the pilgrimage to Mecca that every Muslim must make at least once in their lifetime if they are able; it is the most spiritual event that a Muslim experiences, observing...
Khan Academy
Khan Academy: The Rituals of the Hajj
There are two pilgrimages to Mecca. Hajj--known as the Greater Pilgrimage and 'Umra-the lesser pilgrimage. Hajj can only be undertaken between the 8th and the 13th of Dhu al-Hijja - the twelfth month of the Muslim calendar. At all other...