Ascension Day is officially celebrated on a Thursday on the 40th day of Easter, or 39 days after Easter Sunday. Some churches in the United States join forces to celebrate a combined Day of Prayer and Ascension Day service, which may include a time for reflection. A few churches also organize a "church crawl", where people travel from one church to another and experience the different prayer events.
Ascension Day is one of the earliest Christian festivals dating back to the year 68 CE. According to the New Testament in the Bible, Jesus Christ met several times with his disciples during the 40 days after his resurrection to instruct them on how to carry out his teachings. It is believed that on the 40th day, he took them to the Mount of Olives, where they watched as he ascended to heaven.
Ascension Day occurs ten days before Pentecost and it always falls on a Thursday. However, some churches, particularly in the United States, celebrate it on the following Sunday. Many Eastern Orthodox churches calculate the date of Pascha (Easter) according to the Julian calendar, rather than the Gregorian calendar used by many Western Churches, so their Ascension Day usually occurs after the Western observance.