The Jewish New Year celebration is under way.

Rosh Hashanah, one of four new years on the Jewish calendar, began at sunset on Sunday, Sept. 16 and will last until night falls on Tuesday, Sept. 18.

The holiday marks the beginning of the Jewish High Holy Days. Ten days later comes the celebration of Yom Kippur, the "day of atonement." The 10 days between Rosh Hashanah and Yom Kippur are known as the "Days of Awe."

Rosh Hashanah literally translates to "head of the year," and it takes place during the first two days of Tishrei, the seventh month of the Hebrew calendar. The Hebrew date for Rosh Hashanah is 1 Tishrei 5773.

The Jewish year has four new years, and Rosh Hashanah is considered the new year for people, animals and legal contracts.

During the celebration, Jewish people may greet each other with the traditional Hebrew phrase "shana tovah u'metukah," which means "a good and sweet new year." To match that sentiment, traditional Rosh Hashanah foods include sweet treats like pomegranate, honey cake, raisin challah and apples and honey.

Security is tight in Israel during the New Year celebrations, according to reports from ABC News.

Though the typical holiday closures of Israel's borders with the West Bank and Gaza are being forgone this year, police have beefed up security around areas like the Western Wall, synagogues and busy shopping areas that could be targeted for attack during Rosh Hashanah.