The document summarizes the sub-prime mortgage crisis of the late 2000s. It describes how risky sub-prime mortgages were packaged and sold as securities by investment banks, fueling a housing bubble. When borrowers started defaulting, it led to huge losses at major financial institutions, the bankruptcy of Lehman Brothers, and the acquisition of Merrill Lynch. The crisis spread globally and resulted in the Great Recession, with impacts like millions of foreclosures and a 20% drop in home prices. Governments enacted legislation to regulate derivatives and assist homeowners.