Ash Wednesday takes place 46 days before Easter Sunday, and is chiefly observed by Catholics, although many other Christians observe it too.
Ash Wednesday comes from the ancient Jewish tradition of penance and fasting. The practice includes the wearing of ashes on the head. The ashes symbolize the dust from which God made us. As the priest applies the ashes to a person's forehead, he speaks the words: "Remember that you are dust, and to dust you shall return."
Ashes also symbolize grief, in this case, grief that we have sinned and caused division from God and writings from the Second-century Church refer to the wearing of ashes as a sign of penance.
Priests administer ashes during Mass and all are invited to accept the ashes as a visible symbol of penance. Even non-Christians and the excommunicated are welcome to receive the ashes. The ashes are made from blessed palm branches, taken from the previous year's palm Sunday Mass.