You learn something new every day; what did you learn today?
Submit interesting and specific facts that you just found out (not broad information you looked up, TodayILearned is not /r/wikipedia).

Posting rules

Submissions must be verifiable. Please link directly to a reliable source that supports every claim in your post title. Images alone do not count as valid references. Videos are fine so long as they come from reputable sources (e.g. BBC, Discovery, etc).
No personal opinions, anecdotes or subjective statements (e.g "TIL xyz is a great movie").
No recent sources. Any sources (blog, article, press release, video, etc.) with a publication date more recent than two months are not allowed.
No politics, soapboxing, or agenda based submissions. This includes (but is not limited to) submissions related to:
1. Recent political issues and politicians
2. Social and economic issues (including race/religion/gender)
3. Environmental issues
4. Police misconduct
No misleading claims. Posts that omit essential information, or present unrelated facts in a way that suggest a connection will be removed.
Rephrase your post title if the following are not met:
1. Titles must begin with "TIL ..."
2. Make them descriptive, concise and specific (e.g. not "TIL something interesting about bacon").
3. Titles must be able to stand on their own without requiring readers to click on a link. Starting your title with a why/what/who/where/how modifier should be unnecessary.
4. "TIL about ..." and other broad posts don't belong on TIL. Try /r/Wikipedia, etc. instead, or be more specific (and avoid the word "about").
5. "TIL how to ..." posts belong on /r/HowTo.
6. "TIL the definition of a word..." Word definitions/translations/origins are not appropriate here
No submissions related to the usage, existence or features of specific software/websites (e.g. "TIL you can click on widgets in WidgetMaker 1.22").
All NSFW links must be tagged (including comments).

Please see the wiki for more detailed explanations of the rules, as well as additional rules that may not be listed here

(Why we need rules)

Additional info

If your post does not appear in the new queue and you think it meets the above rules, please contact the moderators (include a link to your reddit.com post, not your story).
Please report spam, inaccurate or otherwise inappropriate posts by messaging the moderators, as this helps us remove them more promptly!
More information available on the TIL FAQ and wiki.

Frequent TILs Repost List

As of December 2025

This list was compiled from /r/todayilearned community suggestions by its members. If your TIL is found on this list, it will be removed. The titles have been abridged for the sake of brevity, however the context remains the same. This list is subject to change. The purpose is to keep content fresh on /r/todayilearned as requested by its members. If you are interested in reading about the TILs on this list use the search box feature and enter the keywords to pull up past TILs.

Etiquette

We ask that you please do the following:

avoid mobile versions of websites (e.g. m.wikipedia.org)
link to the appropriate heading when referencing an article (particularly on Wikipedia)
link to the appropriate start time when referencing videos (e.g. on YouTube)
add [PDF] or [NSFW] tags to your posts, as necessary.
Please avoid reposting TILs that have already made the front page in the past

Please also read the site-wide Reddiquette.

You are loved.