Pentecost is the Greek word for Feast of Weeks. It is celebrated in Israel as Law of Sinai and also in Judaism as Shavuot. In the Christian liturgical year it is a feast to recognise the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ.
This year pentecost was celebrated on May 19th (Western) and June 3rd (Eastern).Pentecost is a feast but also in the celebration of pentecost there is:
The first pentecost was held in the Upper Room, the Upper Room was the location of the Last Supper.