1. In 1889, President Benjamin Harrison signed a proclamation admitting South Dakota as the 40th state in the United States. This followed a long and often contentious struggle for statehood that began in the 1850s.

2. In 1936, the iconic Mount Rushmore National Memorial was formally dedicated. Carved into the granite face of a mountain in the Black Hills region of South Dakota, the sculpture depicts the faces of four U.S. presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln.

3. On August 12, 1972, a flash flood struck the Black Hills town of Rapid City, killing 238 people, most of them asleep in their homes. The flood was caused by a thunderstorm that dumped over a foot of rain in just a few hours, sending a wall of water through the city's streets.

4. In 2016, a team of archaeologists announced the discovery of a rare prehistoric site near the town of Sturgis. The site, which dates back more than 10,000 years, contains evidence of human habitation and hunting, including stone tools and the remains of bison and other animals.

5. On August 12, 1981, the iconic South Dakota State Capitol building in Pierre was added to the National Register of Historic Places. The Capitol, designed and built in the 1920s, features a massive central dome and a grand interior decorated with murals, sculptures, and other works of art.