Ahmed Elgoni felt like he'd struck gold. The 24-year-old video game developer from South Africa had in November secured a ticket to the Game Developers Conference in San Francisco -- a cultural mecca for anyone who wants to make video games. A sponsor would cover the cost of his round-trip flight from Cape Town. Just two weeks ago, he received his visa to enter the U.S. Then President Trump signed an executive order banning refugees and travelers from seven countries. Elgoni grew up in South Africa, but he was born in Sudan -- one of the countries listed as part of the travel ban.

JOHANNESBURG – At first, the drone took some explaining. Anxious villagers buzzed with rumors of a new blood-sucking thing that would fly above their homes. The truth was more practical: A United Nations project would explore whether a small unmanned aerial vehicle, or UAV, could deliver HIV test samples more efficiently than land transport in rural Malawi. Once understanding dawned and work began, young students and their teachers would spill out of the nearby school, cheering, each time they heard the drone approaching. "It was very exciting," UNICEF official Judith Sherman said.