Rosh Hashanah — which means "head of the year" in Hebrew — starts at sunset on September 25, when the Jewish calendar officially flips from the year 5782 to 5783. Most denominations around the world observe Rosh Hashanah with a two-day celebration that includes candle-lighting, blowing a shofar horn and apologizing for the previous year's mistakes.
While the Torah only ordains one day for celebration, the two-day observance is an ancient tradition born of practical necessity, when Jews fled the war-torn province of Judea in large numbers after the Great Jewish Revolt of 66 to 73 A.D. Away from Jerusalem, where the sighting of the new moon signaled the start of the year, the scattered faithful couldn't pinpoint the exact start of Rosh Hashanah. So to ensure that their religious obligations were met, they held two consecutive days of prayer.
Rosh Hashanah kicks off a 10-day period of introspection and repentance known as the Days of Awe, which culminates with Yom Kippur, the Day of Atonement. Many Jews attend synagogue for the traditional prayer service, which includes the confessional prayers Ashamnu and Al Chet, when worshippers gently beat their chests with their fists to symbolize punishment and repentance.
