At its height in the 13th century, the Mongol Empire was the largest contiguous land empire in world history. It stretched across vast territories, encompassing parts of East Asia, Central Asia, and Eastern Europe.
Specifically, the empire extended from the Korean Peninsula in the east to Hungary in the west, covering areas that now include modern-day Mongolia, China, Russia, Kazakhstan, Ukraine, and parts of the Middle East. The total land area of the Mongol Empire at its peak is estimated to be around 13.5 million square kilometers (approximately 5.2 million square miles).
However, it should be noted that the claims such as "from Japan to Ukraine" or "from Australia to Madagascar" are not accurate in the context of the Mongol Empire's geographic boundaries. Japan was never part of the empire, and the Mongol Empire did not reach Australia or Madagascar. The Mongol Empire was primarily concentrated in Asia and parts of Europe, rather than extending to continents like Australia or regions like Madagascar.