1. First Baseball Game in Milwaukee - On April 12, 1870, the first professional baseball game was played in Milwaukee. The game was played between the Milwaukee Cream Citys and the Chicago White Stockings.

2. The First Wisconsin State Parks - One of the first three state parks in Wisconsin, Pattison State Park, was created on April 12, 1918. The park is located in Douglas County and is known for its beautiful waterfalls.

3. University of Wisconsin System Founded - On April 12, 1971, the University of Wisconsin System was created with the merger of the University of Wisconsin and the Wisconsin State Universities. Today, the system includes 13 universities across the state.

4. Spanish Flu Outbreak - On April 12, 1918, the Spanish Flu outbreak reached Milwaukee. The pandemic would go on to kill over 8,000 people in Wisconsin and over 500,000 people in the United States.

5. DeForest Kelley's Birthday - DeForest Kelley, best known for his role as Dr. Leonard "Bones" McCoy in the Star Trek television series and movies, was born on April 12, 1920, in Toccoa, Georgia. Kelley lived in Wisconsin for a period of time and is buried in a cemetery in the state.