Photo taken on April 12, 2020 shows a view of the Fisherman's Wharf amid COVID-19 outbreak in San Francisco, the United States. (Photos: Xinhua)

Photo taken on April 12, 2020 shows a view of the Fisherman's Wharf amid COVID-19 outbreak in San Francisco, the United States.

Photo taken on April 12, 2020 shows a board reminding people to keep social distancing at the Fisherman's Wharf amid COVID-19 outbreak in San Francisco, the United States.

Photo taken on April 12, 2020 shows a view of the Fisherman's Wharf amid COVID-19 outbreak in San Francisco, the United States.

Photo taken on April 12, 2020 shows a view of the Fisherman's Wharf amid COVID-19 outbreak in San Francisco, the United States.