The 1918 influenza pandemic, known as the "Spanish" influenza pandemic, caused approximately 50 million deaths worldwide and remains a significant public health concern. The origins, epidemiological features, and pathogenicity of the 1918 virus are still not fully understood. New genetic sequencing data from archival autopsy tissues have provided insights into the virus's genome, but these data alone do not fully explain its unique characteristics. The pandemic had three distinct waves, with the second and third waves being particularly severe and occurring within a short time frame. The 1918 virus was likely derived from an avian influenza virus and had a novel genetic makeup, making it distinct from other influenza viruses. The high mortality rates in young adults and the rapid spread of the virus across the globe are unique features of the 1918 pandemic. Understanding the 1918 pandemic requires a combination of genetic, epidemiological, and historical analysis, as well as further research into host and environmental factors. Despite advancements in medical knowledge and technology, the potential for another pandemic with similar characteristics remains a significant threat.The 1918 influenza pandemic, known as the "Spanish" influenza pandemic, caused approximately 50 million deaths worldwide and remains a significant public health concern. The origins, epidemiological features, and pathogenicity of the 1918 virus are still not fully understood. New genetic sequencing data from archival autopsy tissues have provided insights into the virus's genome, but these data alone do not fully explain its unique characteristics. The pandemic had three distinct waves, with the second and third waves being particularly severe and occurring within a short time frame. The 1918 virus was likely derived from an avian influenza virus and had a novel genetic makeup, making it distinct from other influenza viruses. The high mortality rates in young adults and the rapid spread of the virus across the globe are unique features of the 1918 pandemic. Understanding the 1918 pandemic requires a combination of genetic, epidemiological, and historical analysis, as well as further research into host and environmental factors. Despite advancements in medical knowledge and technology, the potential for another pandemic with similar characteristics remains a significant threat.