The global financial crisis, also known as the Great Recession, was a period of economic downturn that affected much of the world in the late 2000s. It was triggered by a crisis in the global banking system, which was caused in part by the widespread practice of issuing risky sub-prime mortgages to borrowers who were unable to repay them.

As the housing market collapsed, the value of mortgage-backed securities (which were held by banks and other financial institutions) plummeted, leading to a wave of defaults and foreclosures. This, in turn, caused a credit crunch as banks became hesitant to lend and investors became wary of risky assets. The crisis spread to other parts of the global financial system, and many economies around the world entered into recession.

The global financial crisis had far-reaching effects, including high levels of unemployment, declining asset prices, and a slowdown in global trade. Governments and central banks took a variety of measures to try to stabilize the financial system and stimulate economic growth, including bailouts of troubled financial institutions, monetary policy easing, and fiscal stimulus. The crisis eventually began to abate in the latter part of 2009, but its effects were still being felt in many parts of the world for several years afterward.