At about $15 a gram, saffron is the world's most expensive spice. Rumi Spice has a unique model of employing Afghan farmers who are growing it that aims to double or even triple their annual income. Cristina Hirschkorn/Courtesy of Rumi Spice hide caption

itoggle caption Cristina Hirschkorn/Courtesy of Rumi Spice

Vikram is the first child to wear a Khushi Baby necklace, which will keep track of his immunizations. He's at a vaccine clinic in Rajasthan, India. Ruchit Nagar/Courtesy of Khushi Baby hide caption

itoggle caption Ruchit Nagar/Courtesy of Khushi Baby

Aansoo Kohli is running a makeshift class in a cowshed for children who have no access to school. Abdul Sattar for NPR hide caption

itoggle caption Abdul Sattar for NPR

Norma Melendez, a community health worker with City Health Works, walks along Second Avenue on her way to meet a client. City Health Works is an organization that is attempting to bring an African model of health care delivery to the United States. Bryan Thomas for NPR hide caption

itoggle caption Bryan Thomas for NPR

All folded up and ready to magnify: The Foldscope weighs less than two nickels, is small enough to fit in your back pocket and offers more than 2,000-fold magnification. TED/YouTube hide caption

itoggle caption TED/YouTube

Vital Sounouvou is an African entrepreneur who founded Exportunity.com, a company to help promote trade in Africa. Courtesy of Vital Sounouvou hide caption

itoggle caption Courtesy of Vital Sounouvou