What to do in Modena for a day?

Both on the same day?

Here are suggestions from Bologna and Modena tourism offices:

https://www.bolognawelcome.com/en/blog/top-10-things-to-do-in-bologna-

https://www.visitmodena.it/en/inspire-me/the-10-must-see-visits-in-modena

We stayed in Bologna for 3 nights. The afternoon of arrival we arranged a private walking tour of the downtown area. The 2nd day we took the Bologna Food & Wine Tour #1 by Italian Days http://www.italiandays.it/ It was an all day tour, starting with pick up in Bologna at 7am, touring cheese factory, basalmic vinegar tasting and Prosciutto Factory. Breakfast and lunch included. It was a splurge, ~$300/person, but it was absolutely worth it, a fabulous experience (you don't need to eat breakfast first and you won't want dinner later). Our third day was rainy so we took the local train to Modena and walked to the Ferrari museum, then to the Market in Modena, that was another great way to spend the day. There are also plenty of things to do, just walking around Bologna.