Commemorating the handing down of the Koran to the Prophet Mohammed, Ramadan is time for prayer, friends and family.
It falls on the ninth month of the Muslim lunar calendar and lasts 29 or 30 days, based on visual sightings of the crescent moon.
Muslims also abstain from eating, drinking, smoking and sex during daylight hours to build self-discipline and compassion for those less fortunate.
In doing so Muslims complete one of the five pillars of Islam, the obligations the religion says one must satisfy to live a responsible life.
There are a number of exemptions from fasting - children, pregnant or breastfeeding women, the elderly and those who are ill can all be absolved.
While Ramadan is observed all around the world, specifics can differ by region.
