One of Judaism's holiest days, Yom Kippur, began Oct. 1 and concludes tonight.

Here’s a look at what the holiday means and how Jews around the world observe the day.

What is Yom Kippur?

Yom Kippur, also known as the Day of Atonement , marks the end of the Days of Awe, a 10-day period of introspection and repentance (teshuvah) that begins with Rosh Hashanah.

The holiday is considered Judaism’s most sacred day of the year, sometimes referred to as the “Sabbath of Sabbaths,” and is when Jews are closest to God and to the essence of their souls, according to History and Judaism 101.

When is Yom Kippur?

Yom Kippur is observed on the 10th day of Tishrei, the seventh month of the Hebrew calendar. This year, the holiday began at sunset Oct. 1, and concludes at sunset on Thursday, Oct. 2

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