Final answer:
Ramadan is the month in which Muslims believe the gates of Heaven open and the devils are chained in Hell. It is a time for fasting during the day and is one of the Five Pillars of Islam, including the hajj pilgrimage to Mecca.
Step-by-step explanation:
The month during which it is believed that the gates of Heaven open and devils are chained up in Hell is Ramadan. This is a significant time for Muslims, who engage in fasting (sawm) during the daylight hours, a practice that is one of the Five Pillars of Islam. Ramadan is also the month in which the Quran was first revealed to the Prophet Muhammad. The end of a day's fast is traditionally marked in many Arab cities by the firing of a cannon. Additionally, completing the hajj, another Pillar of Islam, is a lifelong goal for many Muslims, who if able are required to make a pilgrimage to Mecca, in Saudi Arabia. The Islamic calendar, being a lunar calendar, has its months and thus Ramadan move throughout the seasons over the years, leading to varying lengths and conditions for fasting.