Germany: the wreath and the market
Much of what the world thinks of as Christmas came from Germany: the decorated tree, the advent calendar and the Advent wreath, with one candle lit on each of the four Sundays before Christmas.
Then there are the Christmas markets. Dresden's Striezelmarkt was first recorded in 1434, and today almost every German town has a market of wooden stalls selling mulled wine, roasted almonds, gingerbread and handmade ornaments.
Two more dates matter to German children. On the night of December 5 they put their shoes outside the door for St. Nicholas to fill. And in many families presents arrive on Christmas Eve, not Christmas morning.
Try it at home: make an Advent wreath and light one more candle each Sunday, or leave the children's shoes out on December 5.
Mexico: Las Posadas
From December 16 to 24, Mexican communities hold Las Posadas - nine nights that re-enact Mary and Joseph's search for a place to stay in Bethlehem. A procession goes from house to house singing a call-and-response song asking for shelter. At the last house the doors open, and there is food, hot fruit punch and a star-shaped piñata.
The poinsettia, now sold in every supermarket in December, is native to Mexico, where it is called flor de Nochebuena - the Christmas Eve flower. The season runs on until January 6, Día de Reyes, when families share a ring-shaped sweet bread with a tiny figure hidden inside.
Try it at home: hang a piñata on one of the nine evenings, or bake a ring cake with something hidden in it on January 6.
Iceland: the Christmas book flood
Icelanders give each other books on Christmas Eve and spend the evening reading them. So many new books are published in the autumn for this that the season has a name: Jólabókaflóð, the Christmas book flood.
Icelandic children also meet the thirteen Yule Lads, mischievous figures who come down from the mountains one at a time in the thirteen nights before Christmas. Children leave a shoe on the windowsill, and a good child finds a small gift in it in the morning - a naughty one, a potato.
Try it at home: give everyone a book on Christmas Eve, and read together that evening.
Australia: Christmas in summer
In Australia, Christmas falls in the middle of summer. Lunch is as likely to be prawns and salad on the beach as a roast in the dining room, and the afternoon is for cricket in the garden or a swim.
The best-loved tradition is Carols by Candlelight. It started in Melbourne in 1938, and today crowds gather in parks across the country on warm December evenings to sing carols by candle, with the biggest concerts shown on television.
Try it at home: turn the lights off, light some candles and sing two or three carols together.
Bringing them into December
Traditions from other countries make good advent days: a different place each week, a story about how people there celebrate, and something small to try. Christmas Advent Calendar has Christmas traditions from Germany, Mexico, Iceland and Australia behind its doors, alongside carols, recipes and stories to read aloud.