The Bulgarian Orthodox Church marks one of the great Christian feasts - Pentecost. On the fiftieth day after the Resurrection of Christ (Easter), the twelve apostles, together with Virgin Mary, withdrew to the Upper Room on Mount Zion, the building where the Last Supper took place. As they prayed, tongues of fire descended upon them, the visible sign of the influence of the Holy Spirit on Christ's disciples. 

At the end of the church service, walnut foliage is thrown from the altar at the worshipers. It symbolizes the tongues of fires above the heads of the apostles. Believers take it to their homes. The day after Pentecost is known as Monday of the Holy Spirit.