1. In 1899, the first South Dakota State Penitentiary was established in Sioux Falls. The institution was formed to provide proper facilities for confining and punishing those convicted of crimes in South Dakota.

2. In 1929, the Black Hills Flood struck Rapid City, causing widespread destruction and loss of life. Heavy rain fell for over four hours, causing the Rapid Creek to overflow and flood the city's low-lying areas. The deluge resulted in 238 deaths and $237 million in damage.

3. In 1941, South Dakota's Rushmore Mountain Memorial was dedicated. It was carved on the granite face of Mount Rushmore in 18 years by American sculptor Gutzon Borglum and his son Lincoln Borglum.

4. In 1974, the Mount Rushmore National Memorial was added to the National Register of Historic Places. It is one of the most famous landmarks in South Dakota, attracting millions of visitors each year.

5. In 2018, South Dakota State University opened its new Raven Precision Agricultural Center, a state-of-the-art research and training facility. The building contains several labs, classrooms, and technology-equipped greenhouses. It aims to promote the use of precision agriculture practices and further advance agricultural research in South Dakota.