Explore the devastating impact of the 1918 Spanish Flu's second wave on Philadelphia in this 29-minute video, part of the "Mysteries of the Microscopic World" series. Delve into the harrowing details of overflowing military hospitals, premature toe-tagging of soldiers, and the suicide of an Army officer overwhelmed by troop losses. Trace the flu's American origins and its rapid spread from Camp Devens in Boston to Philadelphia, where corrupt inefficiency led to a catastrophic outbreak. Examine the uncertainty surrounding the flu's cause, controversial treatments, and the complete shutdown of public life. Witness the city's descent into chaos as bodies pile up, orphans multiply, and even packs of dogs become a threat. Learn about the virus's mutations, global death toll, and its eventual subsidence in humans while persisting in birds. Gain insights into this once-in-a-century pandemic that claimed 50-100 million lives worldwide and forever changed the course of history.