Yom Kippur, which is also known as the Day of Atonement, is the holiest day of the year in Judaism.
Rosh Hashanah marks the beginning of the Jewish year and the start of the High Holy Days - 10 days which concludes with Yom Kippur.
This year, Yom Kippur begins just before sunset on Sunday September 27 and lasts until nightfall on Monday.
Its central themes are atonement and repentance.
Jews traditionally observe this holy day with a 25-hour long fast and intensive prayer, often spending most of the day in synagogue services.
It is recommended that those observing Yom Kippur also spend as much of the time in between services, reflecting on their misdeeds and asking God for forgiveness.
The end of the period comes with the Neilah service which is marked with a blast of the shofar (an ancient musical instrument typically made of a ram’s horn).
It is traditional to eat a big family meal at the conclusion.
What is the Yom Kippur greeting?
The traditional phrase used is “G'mar Hatima Tova” which translates as “may you be sealed in the Book of Life” and can be shortened to “G'mar Tov”.
However, non-Jewish well-wishers would be better off simply wishing their friends an 'easy feast' or 'good holy day.'