Just days after New York leaders ordered people to stay home, authorities mobilised to head off a potential public health disaster today, the city's emergence as the nation's biggest coronavirus hot spot a warning flare for the rest of the country.
A makeshift morgue was set up outside Bellevue Hospital, and the city's police, their numbers dwindling by the day as more fall sick, were told to patrol nearly empty streets to enforce social distancing.
Public health officials hunted down beds and medical equipment and put out a call for more doctors and nurses for fear the number of sick will explode in a matter of weeks, overwhelming hospitals the way the virus did in Italy and Spain.
Worldwide, the death toll climbed past 20,000, according to a running count kept by Johns Hopkins University. The number of dead in the US topped 800, with more than 60,000 infections.
New York State alone accounted for more than 30,000 cases and close to 300 deaths, most of them in New York City.
Governor Andrew Cuomo, again pleading for help in dealing with the coming onslaught, attributed the cluster to the city's role as a gateway to international travellers and the sheer density of its population, with 8.6 million people sharing trains, lifts, apartment buildings and offices.
"Our closeness makes us vulnerable," he said. "But it's true that your greatest weakness is also your greatest strength. And our closeness is what makes us who we are. That is what New York is."
More than 440,000 people worldwide have been infected overall, by Johns Hopkins' count. More than 100,000 have recovered.
Other American states braced for a version of New York's nightmare, with fears over public events held in the weeks before the virus exploded.
A month after Mardi Gras in and around New Orleans, Louisiana is seeing a ballooning number of cases and now has the third-highest rate per capita in the US, according to the governor. Sixty-five Louisiana residents have died, and the virus has been confirmed in three-quarters of the state's 64 parishes.