In western Christianity, including Roman Catholicism and Protestant denominations, the period prior to Easter holds special significance.
This period of fasting and penitence is called Lent. It begins on Ash Wednesday, and lasts for 40 days (not including Sundays).
The Sunday immediately prior to Easter is called Palm Sunday, and it commemorates Jesus’ arrival in Jerusalem, when followers laid palm leaves across the road to greet him.
Many churches begin the Easter observance in the late hours of the day before (Holy Saturday) in a religious service called the Easter Vigil.
In Eastern Orthodox Christianity, Easter rituals start with the Great Lent, which begins on Clean Monday (40 days prior to Easter, not including Sundays). The last week of Great Lent is referred to as Palm Week, and it ends with Lazarus Saturday, the day before Palm Sunday.
Palm Sunday marks the beginning of Holy Week, which ends on Easter.