Sited within the south Seattle and next to Mercer Island, Seward Park is a pretty decent green spot within the urban sprawl. They have a multi-purpose amphitheater too. There's the tiny rocky beach on Andrews Bay of south Lake Washington that's okay for a chill-out.
A quick sprint along the perimeter works (only 2.4 miles or 4.8 miles up and down), and if we feel like it, we stroll into the very polite and gentle paths in the old growth forest with lots of ferns, red maple, red oak, Douglas fir, Norway spruce, London plane, et cetera. I love all the cones of fir, pine and spruce, and couldn't resist touching them lightly. Collected a few fallen ones to take home.
We sat in the trails and closed our eyes, listening to the sounds of the forest. On a week day, there're fewer people stomping through. Considering this is like a park where residents head to, it isn't even that crowded on weekends. Seattle only has a population of 653,000 people and the city has so many parks that aren't just green patches next to the freeways. Much envy!