This is a list of selected December 31 anniversaries that appears on the "On this day" section of the Main Page. To suggest a new item, in most cases you can be bold and edit this page. Please read the selected anniversaries guidelines before making your edit. However, if your addition might be controversial, or on a day that is or soon will be on the Main Page, please post your suggestion on the talk page instead.
Please note that the events listed on the Main Page are chosen based more on relative article quality and to maintain a mix of topics, not based solely on how important or significant their subjects are. Only 5–6 events are posted at a time and thus not everything that is "most important and significant" can be listed. In addition, an event is not generally posted this year if it is also the subject of the scheduled December 31, 2018 featured article or the December 31, 2018 featured picture.
To report an error when this appears on the Main Page, see Main Page errors. Please remember that this list defers to the supporting articles, so it is best to achieve consensus and make any necessary changes there first.