Map of dreams - Uri Shulevitz

When war devastates their country, a boy and his parents are forced to flee to
another country far east, where they must live in a small room shared with another couple.
Food is scarce.
But one day, when father goes to the bazaar to buy bread, he comes home with a map instead.
The boy and his mother are furious, they are so hungry!
But the map floods their cheerless room with colour.
The boy becomes fascinated by it and is transported far away without ever leaving the room.
Father was right to buy it, after all.