Thousands of Christian pilgrims gathered in Jerusalem on Saturday for an ancient fire ritual that celebrates Jesus' resurrection. The pilgrims crowded into the Church of the Holy Sepulcher, as Eastern Orthodox clerics entered the small chamber marking the site of Jesus' tomb. They emerged after some time to reveal candles lit with "holy fire". The details of the flame's source is a closely guarded secret. The flames are then passed from believer to believer. Eastern Orthodox churches celebrate Easter this week using the older Julian calendar.