Corpus Christi, also known as the Feast of the Body and Blood of Christ, is a significant holiday observed in Vatican City as well as in many other Catholic countries around the world. It is a feast that celebrates the tradition and belief in the body and blood of Jesus Christ and his Real Presence in the Eucharist. The holiday which is based on faith, tradition, and biblical teachings, is a chance for Catholics to bear witness to their faith.

In Vatican City, the holiday is marked with a special mass held by the Pope at St. Peter's Basilica and an annual procession down the streets of Vatican City. This event is one of the most widely attended events in Vatican City, drawing in Catholics from around the world. This procession is a centuries-old tradition, demonstrating public devotion and worship of the Eucharist. The Vatican and Rome's streets are filled with magnificent carpets of flowers for the Pope's Benediction.

Corpus Christi is typically celebrated on the Thursday after Trinity Sunday or the Sunday following that Thursday, depending on the country's tradition. It emphasizes the joy of the institution of the Eucharist, which was established on Holy Thursday in the somber atmosphere of the approaching death of Jesus Christ. While this is a holiday that is deeply rooted in the Catholic Church, it's also a significant social and cultural event within Vatican City, showcasing a deep part of the city-state's identity.