The Kaaba is a large cubical building in Mecca. It is the holiest site in Islam, because Muslims believe that the building was built by Abraham and Ishmael. The Kaaba is the direction Muslims must face during their prayers. One of the most important elements of the Hajj is the Tawaf, or ritual circumambulation of the Kaaba. The Kaaba is located within the Masjid al-Haram mosque.
According to historians, the Kaaba was originally a shrine dedicated to the worship of many Arabic tribal gods. After Muhammad conquered the city in 630 AD, he destroyed the idols housed within the Kaaba to discourage idolatry. The building was rededicated as an Islamic house of worship.