The Black Death, also known as the Bubonic Plague, was a pandemic that devastated Europe and Asia in the 14th century. It is estimated that the outbreak, which began in China in the early 1330s and spread westward along the Silk Road, killed between 75 and 200 million people.
The disease was caused by the bacterium Yersinia pestis, which was carried by fleas that infested rats. The fleas would bite the infected rats and then bite humans, transmitting the bacteria. Symptoms of the plague included fever, chills, muscle aches, and painful lymph nodes (buboes) that appeared in the neck, armpit, or groin. The disease was highly contagious and could be transmitted from person to person through the air.