Saudi Arabia, and specifically the Hejaz, as the cradle of Islam, has many of the most significant historic Muslim sites, including the two holiest sites of Mecca and Medina. One of the King's titles is Custodian of the Two Holy Mosques, the two mosques being Masjid al-Haram in Mecca (which contains Islam's most sacred place, the Kaaba), and Al-Masjid al-Nabawi in Medina, which contains Muhammad's tomb.