As a child, did you have a fort, tree house, play house or something like that which was a retreat for you (and perhaps friends)?

They make very elaborate and expensive tree houses these days, but I think a lot of us had retreats where we went and which grown ups couldn’t get into easily. My friends and I made tepees in the summer and igloos in the winter. One such refuge was simply an apple tree which we climbed, ate green apples and smoked corn silk. Did you have any such special place?