For the past 1,500 years a Holy Fire used to ignites from the tomb of Jesus Christ at the Church of the Holy Sepulchre in Jerusalem. This year too thousands gathered on the eve of Orthodox Easter to pray by igniting the candles from the holy flame.
You may neglect the holy fire as a belief of the Orthodox Christians, especially non-Orthodox Christians. This was a feeling of Orthodox priest Fr Gennady Zaridze too. But he rubbed off his misconceptions when he witnessed the holy fire.
Fr. Gennady was a member of the union of Orthodox scientists to conduct an experiment on the fire. He measured the temperature of the fire using lasers. It was discovered that at the beginning of the fire it was only 42°C. But it increased to 320°C after 15 minutes.
Fr. Gennady now firmly believes that the results were a scientific proof for the existence of Divine energy in the flame.