Rosh Hashanah, ushering in the year 5773 on the Jewish calendar, began Sunday at sundown with the blowing of the shofar, a ram's horn. The holiday starts a 10-day period of penitence and contemplation leading to Yom Kippur, the Day of Atonement, the most solemn and somber day on the Jewish calendar.
In his annual message for the High Holy Days, President Barack Obama called for peace and reconciliation as religious tensions grow at home and overseas.
VIDEO: Watch President Obama's Rosh Hashanah message on YouTube
"This is a joyful time for millions of people around the world. But Rosh Hashanah and Yom Kippur are also opportunities for reflection. They represent a chance to take stock of our lives and look forward to the coming year with clear eyes and renewed purpose," Obama said in a video message.
"I hope that Americans of all faiths can take this opportunity to reach out to those who are less fortunate; to be tolerant of our neighbors; and to recognize ourselves in one another," he said.
"The Jewish New Year is a time of introspection," Rabbi Simcha Backman of Chabad Jewish Center in Glendale said. "It's a time when we look at the year that's past and see what we've accomplished, but more importantly, it's about looking ahead. The main theme is looking forward and being positive."
Because attendance for New Year's services is larger than weekly Sabbath services, some congregations and groups use hotel ballrooms, high school auditoriums, churches and other facilities for their services.