Google made an animated doodle honoring the 148th birthday of the Austrian and American biologist and physician Karl Landsteiner.
In 1901, Landsteiner discovered the existence of blood types A, B, AB and O, and that people of the same or compatible types can receive transfusions from one another. The first successful blood transfusion occurred in 1907 as a direct result of his work, which led to advances in medicine, therapies, and surgery.
Landsteiner is also credited with laying the groundwork, together with fellow scientist Erwin Popper that led to the discovery of the polio virus. This was the first step towards developing a treatment for the disease which affected millions of children worldwide.
World Blood Donor Day celebrated annually on June 14. The theme of the Donor Day this year is "Blood connects us all". It focuses on thanking blood donors.