Can someone explain Securitizations and CDOs and how they contributed to the economic collapse?

Question by Charlie: Can someone explain Securitizations and CDOs and how they contributed to the economic collapse?
I’m writing a research paper and I can’t get a grasp of HOW these aided in the collapse of companies.

Best answer:

Answer by LouBee
It made it easy to unload toxic loans on unknowing investors.

Know better? Leave your own answer in the comments!