1. On February 8, 1858, the Dakota Territory was established. The territory encompassed what is now North and South Dakota, as well as parts of Montana and Wyoming. It was later divided into separate states in 1889.

2. In 1887, the Dawes Act was passed, which aimed to assimilate Native Americans into mainstream American society by allotting them individual plots of land. This act greatly impacted the tribes in South Dakota, such as the Lakota and Dakota, and led to the loss of much of their ancestral lands.

3. On February 8, 1927, the infamous Saint Valentine's Day Massacre occurred in Chicago, Illinois. The murder of seven members of the North Side Gang by Al Capone's South Side Gang had ties to South Dakota, as several of the gang members had been previously located in the state.

4. In 1939, the iconic Mount Rushmore National Memorial was completed in South Dakota. The massive sculpture features the faces of U.S. presidents George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln carved into the granite of the Black Hills.

5. February 8, 2008 saw the opening of the Sanford Underground Research Facility in Lead, South Dakota. This facility is located in the former Homestake Gold Mine and is used for a variety of scientific research projects, including studies on dark matter and neutrinos.