In 1955 a young Japanese girl named Sadako started folding cranes with a wish to cure her own cancer, caused by radiation exposure related to the bombing of Hiroshima. After witnessing the suffering of the children around her, she kept folding cranes, but with the wish for world peace instead of her own cure.
Sadly, Sadako died before she could complete her task, so other children finished the cranes in her memory.
Tsuru, the word for paper cranes, has become a symbol for world peace.
These lovely examples are hanging in the Changi War Memorial, Singapore. These rainbow coloured strands of Tsuru were given to the museum by Japanese school children in a gesture of goodwill and remembrance.