1. On December 21, 1829, the first issue of the "Nashville Banner" was published. The newspaper became one of the most widely circulated daily papers in Tennessee and played a vital role in shaping the state's political and cultural landscape.

2. December 21, 1864 marked the end of the Battle of Nashville, which was one of the most significant battles of the American Civil War. Union forces launched a surprise attack on Confederate troops, which resulted in a decisive Union victory and effectively ended Confederate hopes of regaining control of Tennessee.

3. On December 21, 1958, the first commercial nuclear power plant in the United States began operation in Oak Ridge, Tennessee. The plant produced electricity using nuclear fission, and paved the way for the development of nuclear power plants across the country.

4. December 21, 1977 saw the opening of the Opryland Hotel in Nashville. The hotel featured over 600 rooms, several restaurants, convention centers, and indoor gardens. It quickly became one of the most popular tourist destinations in Tennessee and remained so until it was demolished in 2012.

5. On December 21, 2019, Tornadoes tore through the East Tennessee region, causing extensive damage to homes and businesses. The tornadoes resulted in several fatalities and left many people homeless. Tennessee residents came together to provide support and assistance to those affected by the natural disaster.