For the 1.8 billion Muslims around the world, the Hajj is considered a spiritual pinnacle. Each year, up to three million pilgrims descend on Mecca -- the epicenter of the Muslim world -- to seek redemption, to forgive and to be forgiven. Wrapped in white cloth, worshippers embark on the five-day pilgrimage, considered one of the five pillars of Islam. All Muslims who are physically and financially able are required to make the journey to Mecca at least once in their lifetime. Mecca is meant to be the bedrock of Muslim unity, with the Hajj lauded as a place where pilgrims shed class, race, and nation.