The Second World War was a war in which many terrible things happened. One such event took place on the 6 August, 1945, at 8.15am, Japanese Standard Time. An atomic bomb was dropped on the city of Hiroshima. The atomic bomb exploded 564 metres (1,850 feet) above the ground. Nearly all the buildings within 2.4 km (1.5 miles) were flattened. About 80,000 people died instantly from the blast. Another 70,000 died within a year, from injuries and from the fallout of nuclear radiation in the area surrounding the bomb's detonation.

The deaths did not stop there. Around 200,000 people have died because of this bomb alone. Many died because of illnesses brought about from the high levels of nuclear radiation to which they were exposed from living in and around Hiroshima. Some of those who died due to the bomb were not even born when it was dropped.

Sadako Sakasi

One young Japanese girl named Sadako Sasaki was born in 1943. She was only two years old when the bomb was dropped on Hiroshima. Although she was too young to remember the war, every year she took part in the Peace Celebrations in Hiroshima because her grandmother died during the war. As Sadako grew up, she was strong, courageous and athletic. In 1955, she was preparing for a big race when she became dizzy and fell down. She was diagnosed with leukaemia, a cancer caused by radiation fallout, the 'atom bomb disease'. She was only 11 years old.

The illness changed Sadako's life. She was unhappy because she could not go to school, go out running or do the activities she had so enjoyed. However, she knew that some people recover from leukaemia so she never gave up hope.

The Peace Crane

One day her best friend Chizuko came to visit her and she told Sadako a story to cheer her up. The story was about a bird, a crane which was supposed to live for 1,000 years.

In Japan the crane is known as 'the bird of happiness' and is often referred to as 'Honourable Lord Crane'. The birds are associated with fidelity because they pair for life. They are also symbols of longevity and are often drawn with pine trees, tortoises, stones and bamboo, which are all symbols of long life. Cranes are also associated with good fortune and prosperity so they are often painted with the sun, which is a symbol of social ambition. In many parts of Asia the cries of migrating cranes are a significant signal of the seasons; the crops need to be sown as the cranes depart for their breeding grounds in spring, while their arrival coincides with the harvest in autumn.

Japanese creation myths talk of a legendary warrior who conquered his foes to extend the borders of ancient Japan. On his death, his soul took the form of a crane and flew away. Legend has it that Yorimoto in the 12th Century attached labels to the legs of cranes and asked people who captured them to record their location on the label and re-release the birds, this was a very early program of bird banding to find out about the movements of a species. Some of Yorimoto's birds were claimed to have still been alive several centuries after his death, giving rise to the notion that a crane lived for 1,000 years.

Another legend records that at Kakamura, a feudal leader in the 11th Century, celebrated a Buddhist festival in which birds and animals are set free, by releasing hundreds of cranes as thanksgiving after a successful battle. Each had a prayer strip on its leg to pray for those killed in battle. This appears to be the first recorded association of the crane with celebrations of peace and prayers for those lost in war.

The oldest known use of the motif of a thousand cranes is a 15m (50 foot) long scroll by Sotatsu, an artist of the early 17th Century. The theme was repeated innumerable times in art on screens and walls. Inevitably the crane's reputation for long life and prosperity became a symbol of good health, and origami (the ancient Japanese art of paper folding) cranes became a popular gift for those who were ill.

The story said that anyone who was ill should make 1,000 paper cranes and the gods would grant them a wish.

Sadako hoped that the gods would grant her wish to get well so that she could run again. Her friend, Chizuko showed her how to make a crane using origami and Sadako set to work.

All her visitors brought brightly coloured pieces of paper for her to make the cranes and Sadako's brother hung the finished ones from the ceiling of her room in the hospital.

Sadly, Sadako only managed to complete 644 paper cranes before dying on the 25 October, 1955, at the age of 12. The remaining 356 cranes were folded by her school friends so that she could be buried with 1,000 paper cranes.

A Monument to Peace

Sadako had not given up, she continued to make paper cranes until she died. Sadako's friends were inspired by her courage and determination. They collected the letters that she had written and published them in a book called Kokeshi. Young people all over Japan were touched by her story and raised money to build a monument to her and all of the children killed by the atom bomb.

In 1958 the memorial was unveiled. It is a statue of Sadako holding a golden crane and is in the Hiroshima Peace Park, in Hiroshima, Japan. The statue is engraved at the bottom with the wish the children made:

This is our cry, This is our prayer, Peace in the world

Every year on Peace Day people from all over the world fold paper cranes and send them to Sadako's statue in Hiroshima.

I will write 'peace' on your wings and you will fly all over the world
- Sadako Sasaki