Millions of Muslims around the world broke their fast as the sun went down on Thursday evening, marking the first day of Ramadan, a holy month in the Islamic calendar. During Ramadan, Muslims fasting begin after a pre-dawn meal known as suhoor and end with iftar -- a fast-breaking meal -- at sunset. Eid Al-Fitr marks the end of the holy month of Ramadan. Ramadan is believed to be a time of intense spirituality as Muslims believe that the gates of heaven are open, and Allah's blessings and mercy are abundant. This year, the longest fasting will be in Greenland's Nuuk city for 15 hours and 21 minutes, followed by Iceland's capital Reykjavik for 15 hours and 16 minutes, Finland's capital Helsinki for 15 hours one minute, and Stockholm and Glasgow with nearly 15 hours.