Yom Kippur, the Day of Atonement, is the highest Jewish holy day. It occurs on the tenth day after the start of the new year as calculated by the Jewish calendar system and of the New Year festival. The intervening days are days of penitence. Yom Kippur is a day of renewal and purification, and is thus a strict fastday of self denial. All work is banned and the day is spent in the synagogue, where many prayers of penitence and expiation are spoken. The day of strict fasting expiates offences committed against God and one's fellow man, but only if one has achieved reconciliation with one's fellowman. The sound of the shofar (ram's horn) at the conclusion of prayer marks the end of the Holy Day.