1. May Day Celebrations: May 1 is often associated with the May Day celebrations that were popular in Wisconsin in the late 19th and early 20th centuries. These festivities were held in honor of spring and often included maypole dancing, picnics, and other outdoor activities.

2. International Workers' Day: May 1 is also known as International Workers' Day, which commemorates the Haymarket affair in Chicago in 1886, when police officers killed four people at a labor demonstration. This event spurred the global labor movement and has been a significant date for workers' rights in Wisconsin and throughout the world.

3. German Immigrants: Wisconsin's German immigrants were instrumental in the development of May Day celebrations in the state. Many of these immigrants brought with them the tradition of Maifest, or May Day, which they celebrated in their home country.

4. Progressive History: Wisconsin has a long history of progressive politics and activism, and May Day has been a significant date for many of these movements. For example, in 2011, thousands of people gathered in Madison on May Day to protest Governor Scott Walker's anti-union policies and budget cuts.

5. National Parks Week: In more recent years, May 1 has become associated with National Parks Week, which is held each year from April 17 to May 1. This week-long celebration encourages Americans to explore and appreciate the country's natural beauty and protected areas, including the many national parks located throughout Wisconsin.