Definitely worth a visit when you are in Mainz! There are food vendors (selling cheese, honey,…read morelocal wine, vegetables, etc.) and restaurants (we ended up with fried fish and potato salad--heavy but delicious!), plus a few cafes and a weekly wine tasting (which looked fun but we didn't join this time), all in the shadow of the beautiful cathedral. This is the place to be seen on Saturdays!