Ascension Day is an important Christian holiday celebrated in Vatican City and many other countries worldwide. Traditionally, it is observed on a Thursday, forty days after Easter Sunday. This is because Ascension Day commemorates the belief in the ascension of Jesus Christ into heaven following his crucifixion and resurrection. The holiday holds great spiritual significance for followers of the Christian faith, as it underlines Christ's celestial reign after fulfilling his earthly mission.

Vatican City, as the heartland of the Roman Catholic Church, celebrates Ascension Day with immense reverence and sanctity. The day is typically marked by special church services filled with hymns and sermons about Christ’s ascension. The Pope, as the head of the Roman Catholic Church, gives an address to the faithful, reflecting on the meaning of the event and its implications for followers of the faith. This is followed by large masses, celebrated in St. Peter's Square.

On Ascension Day, Vatican City sees a large influx of believers coming from all corners of the world to participate in the celebrations. Arguably, it is one of the busiest days in the Vatican City's liturgical calendar. The city's magnificent St. Peter’s Basilica becomes a focal point of this religious festivity, brimming with crowds of devout Catholics who gather to pray, commemorate, and gain spiritual blessings on this significant day.