A couple of years ago, during a holidays in Segovia (Spain), I picked some seeds from a couple of trees. I sowed them and eventually, some baby trees were born. I wonder if some of you knows what kind of tree they are. You can see them in Google Maps: https://email@example.com,-4.1259099,3a,38.4y,6h,104.32t/data=!3m6!1e1!3m4!1sKweY1Wbj4qFQs6SXAm_U6g!2e0!7i13312!8i6656
(The brown "leaves" in the branches are some paper-like tulips which have the seeds inside) And one of those I planted so you can see the leaves (We are in a heat wave and my plants are a little bit sad!):
Any clues? Thanks!
Edit: Good news! I moved these to larger pots and pruned them, and they are growing greener and happier. Thanks you all for the advices!