*Includes pictures *Includes accounts of the disasters *Includes online resources and a bibliography for further reading In the 14th century, a ruthless killer stalked the streets of England, wiping out up to 60% of the terror-stricken nation's inhabitants. This invisible and unforgiving terminator continued to harass the population for hundreds of years, but nothing could compare to the savagery it would unleash 3 centuries later. This conscienceless menace was none other than the notorious bubonic plague, also known as the "Black Death." The High Middle Ages had seen a rise in Western Europe's population in previous centuries, but these gains were almost entirely erased as the plague spread rapidly across all of Europe from 1346-1353. With a medieval understanding of medicine, diagnosis, and illness, nobody understood what caused Black Death or how to truly treat it. As a result, many religious people assumed it was divine retribution, while superstitious and suspicious citizens saw a nefarious human plot involved and persecuted certain minority groups among them. Though it is now widely believed that rats and fleas spread the disease by carrying the bubonic plague westward along well-established trade routes, and there are now vaccines to prevent the spread of the plague, the Black Death gruesomely killed upwards of 100 million people, with helpless chroniclers graphically describing the various stages of the disease. It took Europe decades for its population to bounce back, and similar plagues would affect various parts of the world for the next several centuries, but advances in medical technology have since allowed researchers to read various medieval accounts of the Black Death in order to understand the various strains of the disease. Furthermore, the social upheaval caused by the plague radically changed European societies, and some have noted that by the time the plague had passed, the Late Middle Ages would end with many of today's European nations firmly established. In the 17th century, the people of London could boast that they had developed some of the most advanced firefighting technology and methods in the world, including the use of primitive fire engines. There were even vendors of such machines who advertised in papers of their machines' abilities to quench great fires. Of course, even with trained firefighters and new devices, the most skillful efforts could still prove limited in the face of a giant fire, as Rome had learned over 1500 years earlier and as Chicago would learn nearly 200 years later. In fact, one of the primary reasons London developed ways to fight fires was the fact that the city was particularly vulnerable. Although London was over 1500 years old and sat at the heart of the British Empire, most of the buildings were made of wood, and the city was overcrowded, in part due to the fact that city planners worked with and around the ancient Roman fortifications that had been constructed to defend it. As such, while there were spacious areas for the elite and rich outside of the city, London itself had narrow streets full of wood buildings that were practically on top of each other. With some bad luck and bad timing, a potential disaster awaited the city, and that finally came in September 1666. As it turned out, the Great Fire of London was so bad that one author who studied the blaze described it as "the perfect fire," referring to the convergence in the largest city in England of spark, wood and wind in such a way that no one could stop the fire or even fight it effectively. The fire lasted three days, and by the end of it, Londoners were shocked by the wide-scale destruction, which was so great that Samuel Pepys remarked, "It made me weep to see it." In the aftermath, people looked for scapegoats, ranging from King Charles II to the Pope and his Catholic supporters, while England's leaders looked to rebuild the city.