Ramadan is a holy month in the Islamic calendar, during which Muslims across the world fast from sunrise to sunset. Ramadan is also a time of reflection, prayer and charity. 

Ramadan is celebrated during the ninth month of the Islamic calendar, which is a lunar calendar. The exact start date of Ramadan varies each year as it is determined by observing the new moon. This year Ramadan started on March 23rd and ends on April 21st. 

During Ramadan, Muslims are encouraged to focus on their faith and improve their character. Daily fasting is a form of self-discipline and self-control, and it is a way to draw closer to God. Those who fast are encouraged to read the Quran, pray more often, and give more generously to those in need.

Fasting is a practice that has been carried out by Muslims since the earliest days of Islam, and is seen as an act of obedience to God. It is a way of remembering the hunger and thirst of the poor, and it is a way of focusing on the blessings that God bestows daily, such as food, water and health.

During Ramadan, Muslims wake up before dawn for a meal called suhoor. This meal is an opportunity to fill up with energy before the fast, and it is important to get through the day without food or drink. After sunset, Muslims observe a break from the fast, called iftar, with a meal that usually begins with dates and water.

The end of Ramadan is celebrated with a festival called Eid al-Fitr, which is a day of joy and gratitude for having successfully completed the fast. During Eid al-Fitr, Muslims gather with their families and friends to eat and celebrate.

Islam, as the second largest religion in the world, unites about 25% of the world's population. Ramadan is celebrated around the world by nearly a billion people.