The "Bitcoin and Cryptocurrency Technologies" on Coursera helped me gain an understanding cryptocurrencies. Until I took that course I knew very little about the subject.
It's possibly a little dated now, but it's a good primer.
https://www.coursera.org/learn/cryptocurrency/
I'd love to hear what other cryptocurrency courses others recommend.
As many others mentioned, Andrew Ng's course on Machine Learning on Coursera was also very good.