For 10 points, Jews fast for 25 hours on what Day of Atonement?
One ancient ritual on this day involved tying a red band around the horns of a goat and leading it off a cliff. It was the only day that the Kohen Gadol could enter the Holy of Holies. The traditional greeting on the eve of this holiday is "Tzom kal." This holiday, whose five prohibitions include wearing leather shoes and having sex, is bookended by the "Kol Nidre" and "Nei'la" prayers. This holiday occurs on the tenth of Tishrei, nine days after Rosh Hashanah. For 10 points, Jews fast for 25 hours on what Day of Atonement?
One ancient ritual on this day involved tying a red band around the horns of a goat and leading it off a cliff.
Yom Kippur [prompt on Day of Atonement before mentioned]