A good thing that we can extract from society is the culture and arts.
It's actually pretty easy to access its content and learn a lot, discover things for free.
Your first option is to aim for free museums or free expositions. It's not always free unfortunately, but at specific days or age range you can access free entry.
Then, all the knowledge is yours either it's a museum a specific exposition or an art gallery.
You can also in the major cities join some free tours. Someone will provide you with a guided-tour through the city and show you some touristic places (or hopefully not too touristic) and teach you some history about this place.
These "free tours" are often not free but based on suggested donations. Also they are often partners of shops in the cities so don't be surprised if the tour include a visit to some specific shops. Choose your "free tour" carrefuly.
- Botanical gardens are an awesome way to discover some local flowers, trees, plants or just enjoy a refreshing walk a bit disconneted from the city. You'll also find some informative board to learn more about the park or the town.