This page in a nutshell: There are a variety of ways in which editors can contribute to the Selected anniversaries project. The deciding criteria in what gets posted to the "On this day" section of the Main Page each day are NOT solely based on what are "the most important or significant" anniversaries on this day. This is due to the fact that any given day of the year can have a great many historically significant events all eligible to be included, and because relative article quality, along with the mix of topics listed, are also considered.
This set of pages serves as a queue of selected anniversaries which populate the section of the Main Page each day. These pages are also used to help facilitate and coordinate updates to this queue. The selected anniversaries are taken from events in history on each day of the year and holidays/observances from current lunar-based calendars including Jewish, Islamic, and others.
Editors can contribute to the Selected anniversaries project in three main ways:
Identify entries on the project pages that are currently 'ineligible' in the 'staging area' (see next section) and make improvements so that they become eligible. The reason for the entries being ineligible may be, for example, due to criteria 4-6 listed below. Make improvements to the selected article (the boldfaced link in the entry) to resolve the issue(s), then post a message on the project talk page for that day noting the improvements made and that the entry is ready to be considered to move to the 'eligible' section. An administrator or regular editor working on the project will come along to review the improvements and move it to the 'eligible' section in due course.[nb 1]
Make suggestions for new entries to be included in the project pages (see 'Steps for suggesting new listings' below).
Anticipate upcoming anniversaries that are significant or notable (e.g., due to a centenary) and may be particularly worthwhile including in the "On this day" section of the Main Page on that date. Post a message on the project talk page with the suggestions to inform other editors working on the project and complete steps 1 or 2 above to ensure an entry is available for an administrator to use for the "On this day" section on that date.
A list of events and images can be viewed by expanding the 'staging area' on the project page for each day, for example Wikipedia:Selected anniversaries/January 1 (the staging area is not visible when transcluded onto another page, including the Main Page, due to <noinclude></noinclude> tags). Some of these items (the 'eligible' section) are rotated in and out from year to year to form the group that is chosen for the "On this day" section on the Main Page for that day of the year. Other items are listed as 'ineligible' because the event and/or its selected article (boldfaced link) do not pass the selected anniversaries criteria (see below). Making improvements (as described in the section above) so that these entries become eligible is one of the valuable ways editors can contribute to the project.
Admins: If the need arises to remove visible items from a page while it is on the Main Page, please move the items into the 'staging area' if possible, instead of outright deleting them, so they can prospectively be used again in the future.
Be bold while improving this queue but please make sure you follow the selected anniversaries criteria below. Important: although anniversary listings on individual date articles are written in present tense, these selected anniversary listings should be written in past tense to help distinguish them from current events in "In the news" when displayed on the Main Page. A single sentence for each entry is preferable and the link to the selected article should be boldfaced.
If you want to add an item to yesterday's, today's, or tomorrow's listings, you need to be an administrator because those pages are protected. If you're not an administrator, add them to the talk page, such as Wikipedia talk:Selected anniversaries/July 24.
For unprotected days, go ahead and add them directly to the project page, such as Wikipedia:Selected anniversaries/July 26, either in the visible section or in the staging area. If you replace a visible entry, be sure you return the one you removed to the staging area collapsible box.
If you are not sure what to do or how to best phrase the blurb, make your suggestion on that day's talk page.
The criteria for inclusion in the selected anniversaries project pages are subjective due to the fact that any given day of the year can have a great many historical events worthy of listing; relative article quality along with the mix of topics already listed are considered when building OTD sets for each day. Criteria for eligibility are at least:
The event needs to be of moderate to great historical significance (relative to the other historical events that occurred on the same day of the year). It must be important enough to be included in the selected article (boldfaced item) and should also be the most, or one of the most, important events associated with that article. Furthermore, the event should have occurred on the day in question in the calendar in use at the time (per MOS:JG). The date of the event should be determined by the local time, or UTC if local time is not applicable (e.g., not on Earth).
Selected articles (boldfaced items) should comply with the criteria for inclusion listed on Wikipedia:Days of the year.
The selected article (boldfaced item) needs to be updated to clearly state the event or day of the celebration/observance or birth/death, as well as the exact day it occurred/occurs. This is especially true for non-Gregorian-based holidays and observances whose date differs each year. The date mustbecited to a reliable source with an inline citation, since inline citations are used to support specific statements in an article. The only exceptions are recurring holidays that appear on a given day of the week, such as the first Monday of the month. In those cases, the rule itself must be cited, but the actual date for the current year need not be (see WP:CALC).
As of February 2017, we now feature at least one birth and death of a notable person, listed underneath the regular blurbs. This number may be increased if space permits. The criteria for inclusion are:
The article needs to be listed in the BirthsorDeaths section of its corresponding day-of-the-year article (e.g., January 1 § Births), and therefore comply with the criteria for inclusion listed on WP:DOY § Births and deaths.
The article is subject to the same quality requirements as those featured in the blurbs.
People who are listed on their dates of birth may not also be listed on their death dates, and vice versa. Furthermore, if the person is featured (boldfaced item) as a regular blurb on any day, they may not be chosen for birth/death listings (with exceptions, as per below).
As much as possible, the array of topics should include a variety of years (e.g., not just limited to the 20th/21st centuries), geographical areas (e.g., more than just the English-speaking world), and subjects (e.g., not too many articles on war or technology).
Ideally, any particular selected article should only be included as a boldfaced item once in the project pages. To help make sure articles are not selected (boldfaced item) more than once, check the links to that article and examine all the pages listed that begin with Wikipedia:Selected anniversaries/. There is no limit to the number of times an article can be incidentally linked in the project pages (this includes all the non-boldfaced links). Exceptions can be made when any given day is short for eligible articles and the only suitable article already is featured on a different day. In those cases, those articles still should not be selected more than once in the year (i.e., if an article is eligible for inclusion on multiple days, then it should only make one OTD appearance per year). This rule does not apply to holidays/observances, because the same holiday may be celebrated on different dates in different countries, and country articles, because they may be the boldfaced item for holidays such as an Independence Day if the nation's observance doesn't have its own article.
Please note, entries are written in the past tense, preferably in a single sentence.
Images associated with the events can be listed on the project pages for each day. The following criteria apply to images:
Images in landscape orientation are usually set to be 150px wide (120px for portrait-oriented images). Because the image is so small, the subject should be easily distinguished at that size. Judicious cropping may also be employed to highlight a specific aspect of the image (see {{m-cropped}}).
For design purposes, if there is choice between an image of a person facing left and a person facing right, pick the face-left one because it draws the reader's attention toward the associated text, rather than away from it.
Only free images (PD, GFDL, CC etc.) can appear on the Main Page. Non-free images are not permitted.
The visible section of the selected anniversaries pages automatically rotates onto the Main Page each day to populate the "On this day" section. There is maintenance needed before each page appears which follow these guidelines:
Generally 5 events out of those eligible can be chosen for display each day. This number may vary slightly depending on the length of the Wikipedia:Today's featured article and Wikipedia:Did you know sections so that the left and right columns appear balanced without too much empty space. Preference is given to entries celebrating a significant anniversary. For events 100 years old and up, that means multiples of 25 (e.g., 200th, 325th, 550th, etc.). If the event is less than 100 years old, that means multiples of 10 or 25 (e.g., 30th, 60th, 75th).
Holidays/observances should be limited to a maximum of 3, but this may increase to accommodate those that do not appear on the same date each year. Holidays should be listed in this order: international observances (secular followed by religious) first (except those that are not serious in nature, e.g., International Talk Like a Pirate Day—these should appear at the end of the list), then alphabetically by country where observed. When the same day is observed in multiple countries (but not worldwide), then the countries should be listed alphabetically, and the first country used for sorting.
Example (note that these are not actually all on the same date, but combined to demonstrate the sorting): Earth Day (2024); Easter (Christianity, 2024); Mother's Day in Belize and Guatemala; Independence Day in the United States (1776); Star Wars Day
To maintain a variety of topics on the Main Page, an event should not be chosen if it is also related to the subject of the featured article or the featured picture for that particular day.
For births and deaths, when possible try to follow the same rules of thumb: include both births and deaths, include male and female entries, and maintain chronological/geographical/topical diversity.
Only one image/video/audio file should be displayed for any particular day.
Non-Gregorian-based holidays and observances should be moved to the correct day for the current year. When moved, they should not count towards the maximum『3 holidays/observances per day』limit since a number of them might suddenly fall on the same day during a particular year.[nb 2] These holidays and observances should also be marked with the current year in parentheses as an indicator to readers that observance on this day is specific to this year. Certain non-Gregorian holidays may appear more than once per calendar year due the differences between calendars (most notably Jewish or Islamic holidays).
In general, National Days, Independence Days, and other holidays celebrating the nationhood of a country should be marked by the year of the significant historic date being observed. An exception can be made when non-Gregorian-based holidays also fall within the same day, and the non-consistent use of dates might confuse new readers.[nb 3]
Each boldfaced article should be checked to make sure it still qualifies under the selected anniversaries criteria above. For those that do not, there are two options: an alternate boldfaced article can be chosen for the same event if one exists, especially if the original boldfaced article was mergedorsplit. Otherwise, it should be moved to the 'ineligible' section of the staging area with a note indicating the improvements needed.
Make sure to double check, copyedit, and verify each event chosen so it is consistent with the facts presented in the boldfaced article because they may have changed since the previous year.[nb 4]
After making changes, please edit the talk page to indicate what changes were made, following the examples that are already there.
Generally speaking, please apply the guidelines in the following order to determine which items to include:
Give precedence to significant anniversaries (multiples of 100 get the top priority, followed by multiples of 50, while 25 and 10 can be considered equal)
Maintain chronological diversity
Maintain geographic diversity
Maintain topic diversity
Avoid using similar blurbs that are within ±3 days
However, there are times when several of these will come into conflict with each other. For example, on one day in one year, we might have three items that are having their 70th, 75th, and 80th anniversaries respectively, which conflicts with the guideline for chronological diversity. In these cases, please use your best judgement as to how to balance them. So in this hypothetical scenario, maybe one of the three items also featured last year, so you could leave that one out this year. Or maybe two of items are battles in the same war (or two are in the same country), so you could omit the one that appeared more recently. Unfortunately, there is no algorithm that will guarantee that we always have an ideal set of blurbs, so a compromise will have to be made somewhere. As long as you make a carefully considered decision, it will be fine.
2014 – Air Algérie Flight 5017 disappeared from radar shortly after take-off from Ouagadougou, Burkina Faso; its wreckage was found the following day in Mali with no survivors.
^If you have carefully reviewed the entry against all of the criteria below then you can move the entry to the 'eligible' section with a clear edit summary for others to review noting the improvements made.
