> 2008 was bad because the collective banks of the US realized trillions in mortgages were money on the books that wasn't real and was never going to be real.

Don't forget the Europeans. The 'prudent' Germans of Deutsche Bank were in the thick of it too:

* https://www.thelocal.de/20110415/34419

* https://www.reuters.com/article/us-deutschebank-suit-idUSBRE...

See also:

* https://en.wikipedia.org/wiki/List_of_writedowns_due_to_subp...

Good book on how things went down and my who is Crashed:

* https://en.wikipedia.org/wiki/Adam_Tooze#Books