No personal opinions, anecdotes or subjective statements (e.g 'TIL xyz is a great movie'). Videos are fine so long as they come from reputable sources (e.g.

Images alone do not count as valid references. Please link directly to a reliable source that supports every claim in your post title.

Submit interesting and specific facts that you just found out (not broad information you looked up, TodayILearned is not /r/wikipedia).

You learn something new every day what did you learn today?