Hans Rosling (1948-2017) was a Swedish medical doctor, academic, statistician, and public speaker. He was the Professor of International Health at Karolinska Institutet and co-founder and chairman of the Gapminder Foundation, which developed the Trendalyzer software system. He rose to international celebrity status after producing a Ted Talk in which he promoted the use of data to explore development issues.

Hans and Olaf Rosling's speach about how to reduce your ignorance of the world: