Another great pandemic that threatened mankind was the Spanish Flu. It has also been recorded as one of the single deadliest disasters in human history. The flu struck in the early twentieth century and struck very hard. Aided by the First World War, it quickly spread across Europe. The flu was not just limited to Europe; it traveled around the world infecting 500 million people globally. By the end of the pandemic, the death toll had risen to 100 million – about a third of the world population at the time.