World Blood Donor Day is celebrated annually on June 14th to raise awareness about the importance of blood donation. This day honors the birthday of Karl Landsteiner, the scientist who discovered blood groups. It aims to encourage more people to donate blood and to recognize the contributions of voluntary blood donors. The theme of World Blood Donor Day changes each year, focusing on different aspects of blood donation. Events and campaigns are organized globally to promote the need for safe blood and to ensure that everyone has access to life-saving blood transfusions when needed.