Mecca is the holiest city in the Islamic world. Every year, millions of Muslims take a pilgrimage to Mecca, called the Hajj. They follow in the footsteps of Muhammad. All Muslims who are able to perform the Hajj are expected to do so at least once in their life. The Kaaba and Masjid al-Haram, are the holiest mosques in Islam. Mecca is closed to non-Muslims except for some journalists reporting on the Hajj.