Short answers, pulled from the story.
The Federal Reserve began raising interest rates in 2004, ending an era of cheap money that fueled a housing boom. Lenders relaxed standards to issue subprime mortgages to borrowers who could not afford them under traditional rules. Home prices rose by 124% between 1998 and 2006 before values stopped rising and defaults accelerated.
Lehman Brothers filed for bankruptcy on the 15th of September 2008, becoming the largest financial collapse in U.S. history. The firm was once the fourth-largest investment bank behind Goldman Sachs, Morgan Stanley, and Merrill Lynch. Its failure sent shockwaves through global markets causing the Dow Jones Industrial Average to drop more than 500 points in a single day.
Iceland experienced one of the most severe collapses when all three major banks failed between 2008 and 2011. Greece entered a debt crisis in late 2009 leading to years of austerity and social unrest. Developing nations saw foreign direct investment decline sharply after 2008 while Armenia experienced reduced inflows of capital and increased poverty levels.
The Troubled Asset Relief Program authorized $700 billion to purchase toxic assets from banks. Congress passed the Emergency Economic Stabilization Act on the 3rd of October 2008 giving the Treasury Department authority to intervene directly. Over four trillion dollars flowed back into the financial system through Federal Reserve quantitative easing programs.
Unemployment rose from 5% in 2007 to a peak of 10% in October 2009 costing approximately 8.7 million positions nationwide. Median household wealth fell by 35% between 2005 and 2011 dropping from $106,591 to $68,839. One out of every four households lost more than three-quarters of their net worth during this period.