Photos: The Spanish Flu pandemic of 1918

The Spanish Flu was an unusually deadly influenza pandemic, the first of two pandemics involving the H1N1 influenza virus (with the second being the swine flu in 2009). It infected 500 million people around the world, or about 27 per cent of the then world population of between 1.8 and 1.9 billion, including people on isolated Pacific islands and in the Arctic. The death toll is estimated to have been anywhere from 17 million to 50 million, and possibly as high as 100 million, making it one of the deadliest epidemics in human history.