My favorite is probably the parking lot next to my grade school & church. We would do recess there every day from K-8th grade, and I would mill around there on the weekend after mass. It had lots of space and some nice shady areas, an elaborate wrought iron fence on the church side, good walls to bounce tennis balls off, and a couple places to hide and draw in. When I was in fifth grade they painted a big multicolored map of the United States in the middle of the lot which became the foundation for a very specific and elaborate hopscotch-like game. I punched my bully in that lot! Right in the face! Take that, Andrew!
I also have a strong fondness for the parking garage at the office where I worked in the early 2010s — I was really artistically frustrated, closeted, and depressed at that time, and I’d retreat to my car parked on the top level (where nobody else parked) at lunchtime. On nice days I could lay back in my seat and listen to music on my (new!) Smart Phone and there was always a lovely breeze up there. I talked to my friends about being trans while pacing around up there. Felt like a personal haven away from the world.