In the anime "One Piece" they mention a void in history, meaning that they don't know what happened in that period of time. Is there anything similar in our history?
Read Silence in the Sources: History at the Margins from the subreddit's Monday Methods series.
See also what /u/commiespaceinvader has written about why historians will never know everything
/u/mimicofmodes has previously answered How do we study things like common women's fashion in the past when things like dresses and clothes are so often destroyed or lost?