My Watermark is Lake Huron, Ontario.
After my father passed away in Malawi, my mother and I moved to Canada and lived at my grandparents' house (my mother's parents' house). We lived only a short walk from the lake, where I'd play for hours. Walking along the beach with family members is one of my family things to do each time I visit my grandparents' house. It's an activity all my family members can do, regardless of their physical or mental state or age.