 The Hira cave located atop the "Jabal al-Nur" ("Mountain of Light") is located just outside the city and is the location where Muslims believe the Qur'an was first revealed to Muhammad.Visiting Makkah for the Hajj is an obligation upon all able Muslims.The Great Mosque of Makkah, known as the "Masjid al-Haram" is home to the Ka'bah, believed by Muslims to have been built by Abraham and Ishmael, is one of Islam's holiest sites and the direction of prayer for all Muslims ("qibla"), cementing Makkah's significance in Islam.