World War I casualties
The total number of military and civilian casualties in World War I were about 40 million: estimates range from 15 to 19 million deaths and about 23 million wounded military personnel, ranking it among the deadliest conflicts in human history.
Croatia during World War I
In July 1918, first cases of Spanish flu, which killed more than 20 million people worldwide, were reported in Croatia. On average, 60 people were dying in Zagreb per week. In the most difficult period of the epidemic that number has grown to more than 200 people, with a peak in the second week of December, when the number increased to 264. In less than four months, Spanish flu took 700 lives in Zagreb alone, and probably tens of thousands on the whole Croatian territory. Contemporaries evaluated that nearly 90% of the Croatian population was affected in the second half of 1918. Estimate of 15,000 to 20,000 victims in Croatia should be taken as the lower limit of the number of victims of the epidemic.