Yom KippurThe name "Yom Kippur" means "Day of Atonement," and that pretty much explains what the holiday is. It is a day set aside to "afflict the soul," to atone for the sins of the past year.
Yom Kippur atones only for sins between man and G-d, not for sins against another person. To atone for sins against another person, you must first seek reconciliation with that person, righting the wrongs you committed against them if possible. That must all be done before Yom Kippur.
Yom Kippur is a complete Sabbath; no work can be performed on that day. It is well-known that you are supposed to refrain from eating and drinking (even water) on Yom Kippur. It is a complete, 25-hour fast beginning before sunset on the evening before Yom Kippur and ending after nightfall on the day of Yom Kippur.
It is a lovely day not a single car on the road it is so quiet and a slower pace of life for just one day.
The evening service that begins Yom Kippur is commonly known as Kol Nidre, named for the prayer that begins the service. "Kol nidre" means "all vows," and in this prayer, we ask God to annul all personal vows we may make in the next year. It refers only to vows between the person making them and God, such as "If I pass this test, I'll pray every day for the next 6 months!"