According to the Christian calendar, this is the Sunday fifty days after Easter, and is when Christians around the world celebrate the gift of the Holy Spirit.
Pentecost is regarded as the birthday of the Christian church, and the start of the church's mission to the world.
The Holy Spirit is the third part of the Trinity of Father, Son, and Holy Spirit that is the way that we as Christians understand God.
In our own Parish, Pentecost is a happy festival, where our clergy wear vestments with red in the design as a symbol of the flames in which the Holy Spirit came to earth.
Pentecost comes from a Jewish harvest festival called Shavuot. The apostles were celebrating this festival when the Holy Spirit descended on them.