Millions of Christians worldwide ushered in the 40-day season of Lent by imposing the sign of the cross on their foreheads with ash on Wednesday.

Ash Wednesday, which falls 40 days before Easter – not counting Sundays – marks the beginning of a season of reflection and penitence for Christians of the Western traditions.

While Protestants generally do not mark their foreheads with ashes from last year’s Palm Sunday ceremonies – a tradition mainly observed in the Catholic and Anglican churches – they hold special services and give special prayers for repentance and renewal on the holiday.

Often times, in the days leading to Easter, Presbyterians, Lutherans, Methodists, and Episcopalians choose to abstain from eating, drinking or doing certain things to remind them of the Lord’s sacrifice for mankind. Many Baptists, who do not observe Lent, prepare for Easter by reading and meditating on the Bible rather than through ritual.

Among the few Protestants that do use ash in their observances are Lutherans and Methodists.

In the Roman Catholic Church, Ash Wednesday is observed by fasting, abstinence from meat, and repentance-a day of contemplating one's transgressions.

This year, in his message for Lent, Pope Benedict XVI took up the theme of justice, saying that he wants people this Lenten season to reflect on what justice really means for human beings.

Jesus, who fed crowds of followers and healed the sick while he preached, "surely condemns the indifference that even today forces hundreds of millions into death through lack of food, water and medicine," the pope stated in his message, which was released by the Vatican in several languages on Thursday.

"The Christian is moved to contribute to creating just societies where all receive what is necessary to live according to the dignity proper to the human person and where justice is enlivened by love," Benedict added.

Easter this year will be observed on Sunday, April 4, and will be preceded two days before by Good Friday and one week before by Palm Sunday.

In Eastern Christianity, the spiritual preparation for the week leading to Easter begins with Great Lent, which starts on Clean Monday and lasts for 40 continuous days (including Sundays). Clean Monday, this year, falls on Feb. 15.