Walls

The walls of these walls are not like any walls, these are walls fortified with knowledge and reading. These are walls in which we have embedded science to protect us in times of need; so why does the ghoul demolish everything with its feet? And in its free time, it frightens us with its annoying tunes. They are not tunes, but one melody constantly "Zzzzznenenennenennn". Number of pages: 64. Book size: 21*15 cm. Age group: Youngsters.