1. The Mackinac Bridge opened to traffic on December 20, 1957. The bridge spans the Straits of Mackinac, connecting the Upper and Lower Peninsulas of Michigan.

2. On December 20, 1836, Michigan was admitted to the Union as the 26th state. This marked the end of a long territorial period for Michigan and the beginning of its statehood.

3. The first recorded game of ice hockey in the United States was played in Houghton, Michigan on December 20, 1899. The game was played by students from Michigan Tech and was witnessed by a small crowd of spectators.

4. The last coal-fired steam locomotive in Michigan made its final run on December 20, 1955. The locomotive, known as the Pere Marquette 1225, is now a popular attraction at the Steam Railroading Institute in Owosso, Michigan.

5. On December 20, 1927, the Detroit Lions played their first game at the newly constructed University of Detroit Stadium. The Lions defeated the New York Giants 19-0 in front of a crowd of over 26,000 fans.