Growing up in Poland, I have never seen a sweet chestnut tree - we had a number of conker trees, but I had to come to London to discover a sweet chestnut tree!
Two chestnuts: one is toxic and the other edible, one has a very (very, very!) spiky outside and the other much smother one - make sure you use the right ones for cooking and the right ones for playing!
It is now the right time of year to collect both types:
the big shiny ones to make conker people and animals
(just make holes for legs and arms in the 'tummy' conker, use matches or tooth pics to make all the long parts, eyes are made with cloves or small beads pushed in the pre-made holes)
As a child I made these in Poland every autumn. We also used acorns to make animal friends for our conker people.
the ones with a very spiky outside
(nutritious and tasty when boiled or roasted)
Happy picking! Beware of the spikes though...