Yom Kippur, or Day of Atonement, is the holiest day of the year in Judaism.
After leaving Egypt in 1313 BCE, the Jewish people received the Torah from Mount Sinai, hearing the Ten Commandments from God Himself.
When Moses ascended into the mountain and didn't return within 40 days, the Jewish people thought he was dead. And they wanted a new leader.
So they chose a golden calf.
When Moses returned, the people were surprised to see that his face shone from his time in the presence of the Lord.
The holiday is meant as a time of repentance and atonement.
To observe Yom Kippur, some Jews fast and avoid drinking, leather shoes, creams, lotion, bathing or washing and spousal intimacy.
*Clarification: This story has been updated to clarify the language in some cards.