What is a CDO, CDO squared, Synthetic CDO and how did the 2008 crisis happen

Short description of CDO (Collateralized Debt Obligation) and what caused the 2008 collapse --- 5 trillion dollars in pension money, real estate value, 401k, savings, and bonds had disappeared. 8 million people lost their jobs, six million lost their homes. And that was just in the USA. #Finance #CDO #Financialcrisis #Collateralized #SuccessExcellence