2500 years ago Zoroastrianism was the world's most powerful religion, and a major influence on the development of Islam, Judaism and Christianity. Today it is one of the smallest, practised in only a few tiny pockets around the planet, but Tevya manages to meet hundreds of them. He attends a sacrosanct New Year's party and partakes in the sacred coming of age ceremony, Navjote, in the presence of the Zoroastrian's most revered symbol - a fire that has been burning for 3,500 years.