1. 17. OK, some of the important money and medical stuff is over, until I think of more. Next most important: WEAR COMFORTABLE SHOES. Cobblestones can be hard on your feet, especially in 4” high heels or something analogous. ( I read recently that the Italian woman have the walking in skinny, skinny high heels mastered on cobblestones because they put their weight on the ball of their feet, not on the heel: that's the secret.)
18. Europe uses 220 voltage and plugs vary from country to country. There's not euro-plug yet. You can buy adapters at a place like Radio Shack or through travel-supply catalogs.