A man wearing a face mask walks on the National Mall in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People visit the Lincoln Memorial in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People walk past the Lincoln Memorial Reflecting Pool in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People wearing face masks are seen near the Lincoln Memorial in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People wearing face masks visit the National Mall in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People wearing face masks visit the Lincoln Memorial in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People wearing face masks visit the Lincoln Memorial in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
People visit the National Mall in Washington, D.C., the United States, on Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Liu Jie)
Healthcare workers wheel a patient into a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Healthcare workers wheel a patient into a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Pedestrian wearing face coverings walk in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Workers walk in a corridor of a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Healthcare workers tranfer a patient into a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Healthcare workers wheel a patient into a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
A nutcracker sculpture with a mask is seen in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
A pedestrian walks past a COVID-19 test site in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
Healthcare workers tranfer a patient into a hospital in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)
A bus driver wearing a face mask works in New York, the United States, Jan. 1, 2021. The total number of COVID-19 cases in the United States topped 20 million on Friday, according to the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University. (Xinhua/Wang Ying)