Within two years of opening its doors in 1915, the Henry Ford Hospital had already outgrown its home in Detroit. It was slated to move into a new building — until World War I intervened, and the facility, still under construction, was appropriated as a makeshift Army hospital. But as the war began to wind down in September 1918, a new enemy reared its head in the Motor City — and across the nation. 

There had been an influenza outbreak that spring, with the first case of what became known as the Spanish flu reported at Fort Riley, Kansas. (Why was it the Spanish flu if it started in Kansas? Spain, neutral during World War I, was not subject to wartime censorship, and the nation’s press reported on the illness at length, starting when it struck King Alfonso XIII.)

U.S. servicemen brought the disease to Europe, spreading it in densely packed army Army camps — and carried it back with them returning from the war. In That September, soldiers in Massachusetts started falling ill with what was initially believed to be meningitis.

It was the flu — and it quickly spread throughout the United States and the world. The entire city of Cleveland shut down for a month by order of the health commissioner. The dead couldn’t be buried fast enough in Buffalo, leading one enterprising mortician to charge $100 for a funeral within 24 hours. And iIn Detroit, the flu killed 1,688 people — and a bear at the Belle Isle zoo.

With no real vaccination, precautionary measures were similar to those for the COVID-19 outbreak: Wear masks, wash hands and avoid congregation congregating in large groups. By the time the guns stilled in Europe on the 11th hour of the 11th day of the 11th month that year, many restrictions were being lifted. Theaters reopened. Students returned to school. And, most importantly, flu cases and flu deaths dropped. There was a brief resurgence in the spring of 1919, but by that summer, it had lost its lethality, as people built up immunity to it.

But with 675,000 deaths in the United States — and more than 50 million worldwide — it remains the deadliest pandemic in history.