Today marks the beginning of the season of Lent.
It's Ash Wednesday, and many Christians in have their foreheads marked with ashes.
For the next 40 days those who follow the Lenten traditions are expected to pray and do good deeds.
The practice of putting ashes on foreheads dates back to the early Middle Ages.
It was adopted by some other religions in the 1990's.
Lent ends on Easter.