A Black Swan Event is like the Spanish Inquisition of the financial world - it's something that nobody expects, but it can have a huge impact on the market when it happens. It's the kind of thing that makes you go "wow, I did NOT see that coming!"
Example
"The COVID-19 pandemic was a classic Black Swan Event, it came out of nowhere and sent shockwaves through the entire global economy."
"The collapse of Mt. Gox in 2014 was a Black Swan Event for the early Bitcoin community, it shook a lot of people's faith in the whole concept of cryptocurrencies."
