"Ramadan" is the name of the ninth month on the lunar-based Islamic calendar, and its observance through daily fasting from sunrise to sunset is one of the faith's "five pillars," which also include:

• Belief in the oneness of God and the finality of the prophethood of Mohammad;

• Observance of daily prayers;

• Care for the poor; and

• One pilgrimage to Mecca for those who are able.

Muslims believe that Allah, or God, revealed the Quran — the Muslim holy book—to the prophet Mohammad during the month in 610 A.D. In the Quran, Muslims are directed to abstain from eating, drinking and sexual activity during Ramadan.

Exceptions to the fast are allowed by the Quran if one is ill or traveling, with an equal number of alternate fasting days to be substituted. It is believed that the vast majority of more than 1 billion Muslims worldwide observe the fast.