A Thousand Paper Cranes

The one thousand origami cranes were globally popularized through the story of Sadako Sasaki, a Japanese girl who was two years old when she was exposed to radiation from the atomic bombing of Hiroshima during World War II. Sasaki soon developed leukemia and, at age 12 after spending a significant amount of time in a hospital, began making origami cranes with the goal of making one thousand, inspired by the senbazuru legend. In a fictionalized version of the story as told in the book Sadako and the Thousand Paper Cranes, she folded only 644 before she became too weak to fold anymore, and died on 25 October 1955. To honor her memory, her classmates agreed to fold the remaining 356 cranes for her. In the version of the story told by her family and classmates, the Hiroshima Peace Memorial Museum states that she did complete the 1,000 cranes and continued past that when her wish failed to come true. There is a statue of Sadako holding a crane in Hiroshima Peace Memorial Park, and every year on Obon day, people leave cranes at the statue in memory of the departed spirits of their ancestors.

https://en.wikipedia.org/wiki/One_thousand_origami_cranes