I am travelling to France, Switzerland, Italy & Spain for 3 weeks. I am going with my family and its 5 of us in total (2 guys, 3 girls). We will be mostly travelling by trains but will be catching 2 flights as well. We are all planning on buying one backpack/rucksack each where we can fit all our clothes, essentials etc. The limit for plane cabin baggage is 10kg with max dimensions of approx. 55cm x 40cm x 20cm. As we will be doing a lot of walking and might have to go sightseeing with our luggage at times, I am looking for a light, comfortable bag that has plenty of room for 3 weeks worth of stuff.
Any recommendations for bags or what type of bags should I look for in particular?