The Day of Mourning is a day of remembrance for the cataclysm that ended the Last War and destroyed Cyre. It takes place on the 20th of Olarune and is usually a day of the displaced people of Cyre and war veterans talking about the need for remembering this event so it never happens again. In the 4th Edition Ebberron Campaign Guide, an introductory quest takes place during the actual Day of Mourning on the 20th of Olarune 994 YK and again on the 20th of Olarune 998 YK.