Plot: The fourth appointment with Alberto Angela's program begins with extraordinary images in the ice of northern Canada: "Noos - The adventure of knowledge", here a mother bear with her cubs begins a march in search of food to feed herself and her cubs. We will then go to Ravenna to visit one of the state-of-the-art pain therapy departments, then we will talk about food and nutrition, cruise holidays and, with Samantha Cristoforetti, about Mars