At the beginning of 2014, Mt Gox, a bitcoin exchange based in Japan, was the largest bitcoin exchange in the world, handling over 70% of all bitcoin transactions worldwide. By the end of February of that year, it was bankrupt.
Anyone who was using Mt. Gox lost access to their assets, and it has been a cautionary tale for crypto investors. While the assets weren’t all lost, anything that was left has been frozen for years.