The Black Death is thought to have originated in the arid plains of central Asia, where it then traveled along the Silk Road, reaching the Crimea by 1346. From there, it was most likely carried by Oriental rat fleas living on the black rats that were regular passengers on merchant ships. Spreading throughout the Mediterranean and Europe, the Black Death is estimated to have killed 30–60% of Europe's total population. All in all, the plague reduced the world population from an estimated 450 million down to 350–375 million in the 14th century.
