The Global Financial Crisis was the most severe financial crisis since the Great Depression.

Its origins lay in a housing bubble in the United States, which was fueled by low interest rates and lax lending standards.

A key element was the proliferation of 'subprime' mortgages—high-risk loans made to borrowers with poor credit.

Investment banks bundled these risky mortgages into complex financial products called mortgage-backed securities (MBS) and collateralized debt obligations (CDOs).

These products were often given top credit ratings and were sold to financial institutions around the world.

When the U.S. housing bubble burst, a wave of mortgage defaults caused the value of these securities to collapse.

This created a crisis of confidence in the global financial system, as major banks realized they held trillions of dollars in toxic assets.

The crisis reached a pivotal point in September 2008 with the bankruptcy of the major investment bank Lehman Brothers.

This triggered a global panic, the freezing of credit markets, and a steep decline in stock markets.

The crisis led to massive government bailouts of financial institutions and a deep global recession known as the 'Great Recession.'