Dr. Ryan Padgett is back home in Seattle after a 24-day hospitalization for COVID-19. He was one of the first American health care workers to develop a life-threatening case of the disease. Martin Kaste/NPR hide caption

Close-up of modern flax cordage showing twisted fiber construction. S. Deryck hide caption

The ancient Takizakura cherry tree, in Miharu, Japan, in March, just days before bursting into bloom. A pathway for tourists at the base of the tree will see less use this year, due to the coronavirus pandemic. Claire Harbage/NPR hide caption

Michigan Gov. Gretchen Whitmer addresses the state during a speech in Lansing, Mich., on Monday. Whitmer says she's listening to "the best medical advice" on when to ease restrictions. Michigan Office of the Governor via AP hide caption

Public health experts say smartphone apps could augment the time-consuming work of tracking down people who have been exposed to the coronavirus. Bloomberg/Bloomberg via Getty Images hide caption

Zhang Hai stands on a bridge where he took his father out for a walk only about four months earlier. His father died of the novel coronavirus on Feb. 1. "The scenery is still here, but the person is gone," he sighs. He says he frequently comes to this park "looking for memories." Amy Xiaomeng Cheng/NPR hide caption