In coming years, families around the world will be reminded of what happened in January 2021 by gaps in photo albums, saved video chats or text message threads, and in some cases, tragically, empty seats at future weddings. But in the history books, the pandemic’s impact will be traced in terms of milestones, including one passed on Friday: 2 million people have died from the COVID-19 pandemic, according to the Johns Hopkins Coronavirus Resource Center.