When does Lent 2017 start and what is Ash Wednesday? The meaning behind the Christian tradition and 40 days of fasting

A Catholic nun marks a woman's head with ash in Bamako's cathedral, Mali Photo:BBC

Millions of Christians are preparing to celebrate Lent - a time of year that many non-believers may associate with fasting or abstinence.

But there is a lot more to the religious observance than giving up something, as it is regarded as a period of spiritual preparation to grow closer to God in the run-up to Easter.