Age: 16 

The self-taught teenager never had the luxury of taking engineering classes in his home country of Sierra Leone. Yet at 13 years-old, Doe was able to create batteries and generators out of spare parts and resources from trashcans, which he used to power his own community radio station and family home. All with the help of some scrap metal, baking soda, and acid. Doe remains the youngest person in history to be invited to MIT’s Visiting Practitioner’s Program for international development.