With unique access to Islam's holiest city, National Geographic's " Inside Mecca " follows three Muslims from very different backgrounds as they embark on an epic five-day reaffirmation of faith and quest for  salvation  " Inside Mecca " captures the look and feel, spiritual uplift, claustrophobia, grandeur and grit of the largest annual gathering of Muslims in the world. "' Inside Mecca ' focuses on the personal stories of the hajj," says Anisa Mehdi, producer and director of the film. "Through the various viewpoints and experiences of the participants, we follow not only their physical steps but the spiritual and emotional stages of this all-important voyage. We want to show viewers around the world the remarkable experience of the hajj: that it is at once deeply personal and widely universal." One of the five pillars of Islam, the hajj is required of all who can manage it at least once in a lifetime. Each year, Muslims from all over the world travel to Makkah to praise and give thanks to God, to ask pardon for their sins and to renew their spiritual commitment through an elaborate series of rites and rituals.