Climbing a large tree with low hanging branches on the bank of the local canal, with a Ladybird book and half an apple. I definitely wouldn't allow my children to do that today! We weren't aware of consequences in those days, the branches didn't overhang the canal and the low branches were good to lean back against the thick tree trunk, we could watch the barges moving along the canal and cross over the stone bridge to go to the chandlers and the little shop attached, they sold lovely ice-creams! (Note the half apple, we had to share apples because of the expense).