In this Jan. 27, 2020, photo, members of a group of foreign tourists wearing face masks to protect against the coronavirus walk through a public park near the Forbidden City in Beijing. The U.S. has issued a new advisory Tuesday, Sept. 15, 2020, warning against travel to mainland China and Hong Kong, citing the risk of "arbitrary detention" and "arbitrary enforcement of local laws." (AP Photo/Mark Schiefelbein)