Tennessee furnished more soldiers for the Confederate Army than any other state besides Virginia , and more soldiers for the Union Army than the rest of the Confederacy combined . Beginning during Reconstruction , it had competitive party politics , but a Democratic takeover in the late 1880s resulted in passage of disenfranchisement laws that excluded most blacks and many poor whites from voting . This sharply reduced competition in politics in the state until after passage of civil rights legislation in the mid-20th century . In the 20th century , Tennessee transitioned from an agrarian economy to a more diversified economy , aided by massive federal investment in the Tennessee Valley Authority and , in the early 1940s , the city of Oak Ridge . This city was established to house the Manhattan Project 's uranium enrichment facilities , helping to build the world 's first atomic bombs , two of which were dropped on Imperial Japan near the end of World War II . After the war , the Oak Ridge National Laboratory became a key center for nuclear research . In 2016 , the element tennessine was named for the state
world 's first atomic bombs
Trinity (nuclear test)
Tennessee