<span>more than 100 million acres of land</span>
John Paul Jones refused to surrender his ship and George Rogers Clark led his troops through freezing swamps and surprised the British.
The use of check and balances.
One of the main reason why more people didn't foresee the economic collapse of the 1930s is because it happened so quickly with no warning, since the US economy during the 1920s was incredibly strong and showed no signs of slowing.