The Black Death consisted of three plagues - Bubonic, Pneumonic, and Septicemic - caused by the Yersinia pestis bacteria, which was transmitted via fleas living on rats. The Bubonic plague was the most common type and symptoms included fever, chills, and swollen lymph nodes called buboes. It killed an estimated 100,000 people in the 1665 Plague of London. The Black Death had lasting effects on European civilization through population decline, economic impacts, and changes in art and literature.