Folding 1,000 origami cranes, senbazuru is a tradition that originated from an ancient Japanese legend. The legend claimed that anyone who folded 1,000 paper cranes would be granted either a lifetime of happiness, good luck, or one wish. The practice became more widely popularized after the death of 12-year-old Sadako Sasaki in 1955.
Sadako Sasaki was two years old when the United States dropped an atomic bomb on the city of Hiroshima. Ten years later, Sadako developed leukemia as a result of radiation exposure and was hospitalized for treatment. After learning about the legend of 1,000 cranes from her father, Sadako attempted to fold 1,000 cranes from her hospital room, hoping it would grant her a wish. An exhibit about Sadako at the Hiroshima Peace Memorial Museum states that she completed her goal before she passed away on October 25th, 1955.