The number one cause of death globally throughout history is infectious disease. Infectious diseases have ravaged human populations since the dawn of civilization and continue to be a major cause of morbidity and mortality worldwide, contributing to more deaths than any other single factor. Historically, pandemics such as the Black Death (bubonic plague) in the 14th century, the Spanish Flu pandemic in 1918-19, and more recently, the COVID-19 pandemic have caused staggering loss of life on a global scale. However, it's important to note that advancements in medical science, public health measures, and improved sanitation have significantly reduced the impact of many infectious diseases in modern times.