In a span of only three years, the Black Death/bubonic plague rapidly spread across Europe, killing upwards of twenty-five million people. The bubonic plague not only killed more people than any other disease, but it is also one of the most easily transmitted diseases, and is practically incurable.

The European population before the Black Death, in 1347, was about seventy-five million, but a few years after the plague had died down, in 1352, the European population was about fifty million! That means that one in every three people died! The plague's first outbreak was in Pelusium, Egypt, in the sixth century. Then it slowly spread across Europe, following the Mediterranean Sea. So many people were dead that there weren't enough graves to house them. "Extra" bodies were sometimes burned, or even left in homes to rot. Classic symptoms of the bubonic plague include feeling sick, very high fever, chills...