Rosh Hashana will begin Sunday evening this year. Here, an Ultra-Orthodox Jew tests a horn at a horn factory in Tel Aviv, Israel, in preparation for the celebration of Rosh Hashana, Reuters

For Jews, the new year begins with the celebration of Rosh Hashana, a holiday regarded as one of the holiest days in the Jewish faith. Each year, the two-day holiday falls on a different day since the Hebrew calendar determines the date.

This year, Rosh Hashana will start at sundown Sunday. Even though the date changes, the holiday tends to fall between Labor Day and Columbus Day and lasts for two days.

The dates of the celebration vary from year to year because the Jewish calendar goes by lunar cycles instead of the sun. As a result, the Jewish calendar has about 11 fewer days than the solar calendar. Jews are not the only ones who refer to a lunar calendar -- the Chinese and Muslim calendars are also based on the moon.

In the Torah, the holiday is referred to as Yom Teruah -- the Day of the Sounding of the Shofar -- and Yom Ha-Zikkaron, the Day of Remembrance.

The term Rosh Hashana may literally translate to "Head of the Year," but unlike New Year's Day, the holiday does not mark the start of the calendar. The Jewish new year occurs on the first day of the seventh month of Tishri, instead of the first month, Nissan. However, Rosh Hashana is when the year number is increased by one.

One thing that the American New Year's Day and Rosh Hashana have in common is that both are used to reflect on the past year. Jews plan for the next year, and also repent for their sins and those they have wronged.

The Jewish belief is that G-d begins to determine everyone's fate for the next year on Rosh Hashana. This process known as "teshuvah" ends with another holy day in the Jewish faith, Yom Kippur.

Jews attend temple services on both days of Rosh Hashana and families come together to have a feast to celebrate.

This year, Rosh Hashana ends Tuesday evening at sundown.