Hanukkah, the Festival of Lights, lasts eight days from the 25th of Kislev in the Hebrew calendar - in late November or December. It remembers the rededication of the Temple in Jerusalem after the Maccabees' revolt in the second century BCE, when, the story goes, one day's oil kept the menorah burning for eight.

Like every Jewish day, it begins at sundown: the first candle is lit on the evening before the first day, and one more each night after, lit from the shammash, the helper candle set apart from the rest.

Christmas celebrates the birth of Jesus. By the fourth century the church in Rome kept it on December 25, close to the winter solstice, when midwinter festivals of light were already held - and lights, evergreens and the star on the tree still brighten the darkest time of the year.

Many Orthodox churches, which follow the older Julian calendar, keep it on January 7.