From Indonesia to Egypt, Muslims around the world have started celebrating Ramadan this week (because the holy month begins with the sighting of the new moon, the start date varies from country to country). The holiday marks the ninth month of the Islamic calendar -- when the Quran, Islam's central religious text, was revealed to the Prophet Muhammad. Muslims fast from sunrise to sunset and abstain from drinking, smoking, and sex, giving those who observe the holiday a chance to purify their souls and focus on Islamic teachings.
While Ramadan isn't immune from commercial influence -- businesses have marketed everything from designer chocolates to expensive break-fast meals, while also taking advantage of the surge in social media use during the holiday -- it is still widely observed. In a recent Pew survey of 38,000 Muslims in 39 countries and territories, a median of 93 percent of respondents said they fast during the holy month.
Above, Muslims pray in the first Tarawih to mark the start of the month of Ramadan in Cheng Ho Mosque on July 9 in Surabaya, Indonesia.