The Day of Atonement, also known as Yom Kippur, is the most solemn day in the Jewish calendar. Yom Kippur is centered around repentance and and atonement and involves 24-hour fasting and deep, intensive praying. The feast is observed on Tishrei 10, in accordance to God’s command in Leviticus.

"On exactly the tenth day of this seventh month is the day of atonement. It shall be a holy convocation for you, and you shall humble your souls and present an offering by the fire to the Lord."
- Leviticus 23:27

Fasting begins thirty minutes before sundown on the eve of Yom Kippur, and besides fasting and praying, five other prohibitions are traditionally observes on Yom Kippur, including eating and drinking, wearing leather shoes, bathing/washing, anointing oneself with perfumes or lotions, and marital or sexual relations. The afternoon before Yom Kippur, Jewish families celebrate a large festive meal and Orthodox Jews cleanse their bodies in a ritual mikvah. People visit family and friends and ask for forgiveness for any wrongs they may have committed against them in the previous year.

By law on Yom Kippur  in Israel there are no t.v. broadcasts, store and markets are closed, the Ben Gurion airport shuts down, public transportation is not available. The only exception was in 1973 when a air siren was sounded and broadcasts were sent on the radio to notify the state of Israel that they were under suprise attack in the Yom Kippur War. 

In Christian traditions, Yom Kippur traditions are mixed into both Ash Wednesday and Good Friday. Ash Wednesday marks the beginning of the Lenten season and is meant to seek repentance on one’s sins. Because Yeshua died on Good Friday, He is the ultimate atonement of everyone’s sins. Both days call for fasting and abstinence and are solemn days in the Christian calendar.