Aesculus hippocastanum Fr: Marronnier
The Horse Chestnut grows to about 25-30 m high, with a large, rounded shape, and the trunk is thick and usually short. It's used widely in our Beyond region as a shade tree in parks and village squares (although not quite so common as the plane tree). The tree in our photo here is at the village of Mons.
The fruit of the horse chestnut is a spiny, green sphere about 4 cm diameter. When it ripens, the thick green husk splits to reveal one or more smooth brown nuts.
In Britain, the inedible nut is called a conker. Its main use is for a game: With your favorite conker tied to a string, you swing it against your competitor's conker until one of them breaks. The winner (with the unbroken conker) takes on all comers until the king of the conkers is established.