TOPSHOT - US President Joe Biden, First Lady Jill Biden, US Vice President Kamala Harris and her husband, Doug Emhoff, hold a moment of silence during a candelight ceremony in honor of those who lost their lives to Coronavirus on the South Lawn of the White House in Washington, DC, February 22, 2021. - President Joe Biden called the milestone of more than 500,000 US deaths from Covid-19 "heartbreaking" on Monday and urged the country to unite against the pandemic. "I know what it's like," an emotional Biden said in a national television address, referring to his own long history of family tragedies. (Photo by SAUL LOEB / AFP)