The COVID-19 epidemic had only recently begun to spread internationally in 2020. This sparked widespread panic and uncertainty in financial markets, resulting in severe drops in worldwide markets... bitcoin was no exception.
Bitcoin's price plummeted by 50% (FIFTY PERCENT) in a single day exactly three years ago.
This resulted in a massive liquidation cascade on the once-popular exchange BitMEX. In a couple of minutes, $750 million in bitcoin was liquidated. This resulted in a quick decrease to the low of $3600... the exchange was then conveniently closed for "maintenance" (Its owner, Arthur Hayes, received a two-year probation sentence for money laundering.)
Deribit, another major exchange at the time, experienced technological troubles as well.
Nonetheless, bitcoin's price recovered fully in two months and eventually set a new all-time high...