A newly identified coronavirus, SARS-CoV-2, is spreading across the globe. Most of our work focuses on large problems that humanity has faced for a long time, such as child mortality, natural disasters, poverty, and almost 100 other problems. This article focuses on a new, emerging global problem: the ongoing outbreak of the coronavirus disease (COVID-19). The outbreak started in China in late 2019, and by March 2020 the disease has spread to countries around the world. The number of infections appearing each day has since plummeted in China, owing in large part to containment efforts, but the outbreak is now a global pandemic. Large outbreaks in South Korea, Iran, Italy, and elsewhere have propelled a spike in international cases across more than 180 countries.