Nevertheless, Mecca and Medina remained the spiritually most important places in the Muslim world. The Quran requires every able-bodied Muslim who can afford it, as one of the five pillars of Islam, to make a pilgrimage, or Hajj, to Mecca during the Islamic month of Dhu al-Hijjah at least once in his or her lifetime. The Masjid al-Haram (the Grand Mosque) in Mecca is the location of the Kaaba, Islam's holiest site, and the Masjid al-Nabawi (the Prophet's Mosque) in Medina is the location of Muhammad tomb; as a result, from the 7th century, Mecca and Medina became the pilgrimage destinations for large numbers of Muslims from across the Muslim world.