The U.S. subprime mortgage crisis was caused by lending too much money to people who couldn't pay it back, leading to a housing market crash. This crisis spread to other countries and had a big impact on the U.S. economy, causing housing prices to drop, less spending and investing, and fewer jobs. The crisis isn't over yet, and things don't look good for the future. To fix this, we need to look at how to avoid risks in lending, balance the economy better, use monetary policies effectively, and fix internal and external imbalances.