1. On April 5, 1920, the Wisconsin State Assembly passed legislation making Wisconsin the first state in the US to mandate the teaching of conservation in its public schools. The law required a course in conservation to be taught in all primary and secondary schools in the state, with the aim of educating students about the importance of natural resources and the need to protect them.

2. On April 5, 1951, the University of Wisconsin-Madison became the first university in the country to offer a PhD in computer science. The program was established in response to the growing importance of computers in research and industry, and the need for trained professionals to develop and manage these technologies.

3. On April 5, 1987, the Milwaukee Brewers played their first ever game at Miller Park, the team's new stadium located in downtown Milwaukee. The stadium, which replaced Milwaukee County Stadium, was the first stadium in the US with a retractable roof and features numerous amenities for fans.

4. On April 5, 1989, Milwaukee police officer John Malloy became the first officer in the US to be convicted of murder for an on-duty shooting. Malloy shot and killed a fleeing suspect in 1988, and was found guilty of second-degree murder following a controversial trial that divided the community and sparked national debate about police use of force.

5. On April 5, 2003, Wisconsin native Matt Kenseth won the NASCAR Cup Series race at Texas Motor Speedway, marking his third career victory in the series. Kenseth, who grew up in Cambridge, Wisconsin, went on to win the Cup Series championship later that year, becoming the first Wisconsin driver to win the title in the modern era of NASCAR.