The Tuskegee Airmen were the first black military aviators in the U.S. Army Air Corps (AAC), a precursor of the U.S. Air Force. Trained at the Tuskegee Army Air Field in Alabama, they flew more than 15,000 individual sorties in Europe and North Africa during World War II.
The main reason was the South wanted to preserve slavery. The North wanted to abolish it. If you want some other reasons than slavery, let me know, and I will do my best to add more to this answer.
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Throughout the mid-1880s, the Northern Pacific pushed to reach Puget Sound directly, rather than by means of a roundabout route that followed the Columbia River. Surveys of the Cascade Mountains, carried out intermittently since the 1870s, began anew.