Witnessing one of the 20th century's worst acts of brutality seared my memory.

There were two lines at the Monrovia airport that morning in 1990.

Both groups were trying to flee the rival militias who had surged into Liberia's capital, raping, maiming and killing. Rajesh Panjabi and his family stood in one line, with those who could afford to evacuate on the relief planes. They were able to escape. People in the other line—indigent Liberians—did not. Panjabi never stopped thinking about them or the other countless millions perpetually trapped in life's "other line." He's dedicated himself to preventing their suffering.

Since then he has pursued a medical degree (with a specialty in infectious disease), lobbied Capitol Hill for HIV funding and promoted maternal health in Afghanistan. "Through collaboration with people in poor and volatile environments like Africa, Afghanistan and impoverished U.S. neighborhoods, I am learning how to take action that addresses people's most fundamental needs," says Panjabi.