Horse chestnut
A horse chestnut (Aesculus hippocastanum), also known as the horse-chestnut, buckeye, conker tree, or Spanish chestnut, is a large deciduous tree. It is native to southern Europe, in the Balkans. It is often grown in temperate climates. It can grow up to 36 metres tall.  The name of the tree (and the whole genus of similar trees) is because its fruit, the conker, was used to treat horses, against cough and some parasite worms.