There is on place in Petersburg I just love. But only in the summer.

Go to field of Mars (марсовое поле) and in the top left corner, looking from the Neva, there are some trees. Two of the trees are close enough and slanted enough that you can sit with your back reclined on one of the trees, and your feet up on the other (if you so like). On one of the trees there is even a branch that is perfect for hanging a jacket. Just sit there and watch people go past... *memories*