"Черная смерть" (Black Death) was a devastating pandemic that struck Europe in the 14th century, peaking between 1347 and 1351. It was caused by the bacterium Yersinia pestis, which was transmitted through fleas that infested rats. The disease led to the deaths of an estimated 25 million people, roughly one-third of Europe's population at the time. The Black Death had profound social and economic effects, leading to labor shortages and changes in land use. It also contributed to shifts in religious beliefs and practices, as many people sought explanations for the catastrophe. The pandemic marked a significant turning point in European history.