My Watermark is Lake Ontario.
One day in June a few years ago I walked with my daughter, Elena, and her partner, Liam, the full 8 km length of the dunes peninsula at Sandbanks Park, near Picton. It tapered steadily until it was just a few meters across. On one side, to the west, Lake Ontario receded like a sea and on the other side was the gorgeous lagoon of West Lake. We were running a gauntlet between two bodies of water. When we reached the tip of the peninsula -- water on three sides now, almost surrounding us -- we swam across a forty meter channel into the town of Wellington.
What a day that was. And what a gift it is to have a place like that available all year round. I think I've just talked myself into going back there this weekend and doing that walk again.