Too Long; Didn't Read
On June 19th 2011, the largest Bitcoin exchange, Tokyo-based Bitcoin exchange Mt. Gox reported to their users that they had lost approximately 850,000 Bitcoin in multiple ways, which at that time was worth $450 Million USD (Or about $10B USD now). This was by far the largest loss in the history of cryptocurrency and had a severe impact on the price of Bitcoin. An unusual series of mistakes was made which enabled the money to be stolen, or lost in several forms. Mt Gox is one of the main examples why <a href="https://hackernoon.com/what-you-need-to-know-about-managing-crypto-investments-b5d0852f9b91" target="_blank">we recommend</a> keeping money in cold wallets rather than wallets at exchanges.