Here are 5 interesting facts about October 15 in Iowa history:

1. In 1926, a groundbreaking ceremony was held for the construction of the largest engineering project in Iowa's history, the Saylorville Dam. The dam was built to control flooding and generate hydroelectric power on the Des Moines River.

2. In 1940, the Iowa-Iowa State football game was played at Drake Stadium in Des Moines due to renovations at Iowa's stadium. A crowd of over 30,000 watched Iowa defeat Iowa State, 7-0.

3. In 1964, musician Johnny Cash performed at the National Cattle Congress in Waterloo, Iowa. The show was recorded and later released as the album "Johnny Cash at the Cattle Call."

4. In 1998, a dedication ceremony was held for the Herbert Hoover Presidential Library and Museum in West Branch, Iowa. The library and museum contain artifacts, documents, and exhibits related to the life and presidency of Herbert Hoover, who was born in Iowa.

5. In 2016, the Sioux City Public Museum opened an exhibit titled "Nazi Persecution of Homosexuals 1933-1945." The exhibit, which was on loan from the United States Holocaust Memorial Museum, explored the history of the Nazis' persecution and marginalization of gay and lesbian people during the Holocaust.