1. Statehood Day: April 1 is a significant day in South Dakota's history as it marks the state's Statehood Day. On this day in 1889, President Benjamin Harrison signed a proclamation admitting the Dakota Territory as two states, North and South Dakota.

2. Mount Rushmore: On April 1, 1925, sculptor Gutzon Borglum began work on Mount Rushmore, the iconic American landmark featuring the carved heads of four former U.S. presidents – George Washington, Thomas Jefferson, Abraham Lincoln, and Theodore Roosevelt.

3. Blizzard of 1997: On April 1, 1997, a severe blizzard hit South Dakota, causing widespread damage and resulting in the loss of millions of dollars in livestock. The storm also claimed a number of human lives and caused travel disruptions that lasted for days.

4. History of Agriculture: South Dakota has a rich agricultural history, and April 1 is an important day for farmers as it marks the start of the planting season in the state. This is a time of hope and new beginnings as farmers prepare to sow their fields for the upcoming harvest season.

5. Discovery of Mammoth Bones: On April 1, 1974, a farmer in South Dakota made an incredible discovery when he unearthed the bones of a woolly mammoth on his land. The find attracted worldwide attention and shed new light on the prehistoric history of the region.