Which was the largest contiguous land (Empire) in the world?

The Mongol Empire existed during the 13th and 14th centuries; it became the largest contiguous land empire in history. Originating in Mongolia, the Mongol Empire eventually stretched from Eastern Europe and parts of Central Europe to the Sea of Japan, extending northwards into Siberia; eastwards and southwards into the Indian subcontinent, Indochina and the Iranian Plateau; and westwards as far as the Levant and the Carpathian Mountains.

The Mongol Empire emerged from the unification of several nomadic tribes in the Mongol homeland under the leadership of Genghis Khan (c.1162 - 1227), whom a council proclaimed ruler of all the Mongols in 1206. The empire grew rapidly under his rule and that of his descendants, who sent out invading armies in every direction. The vast transcontinental empire connected the East with the West in an enforced Pax Mongolica, allowing the dissemination and exchange of trade, technologies, commodities and ideologies across Eurasia.

The empire began to split due to wars over succession, as the grandchildren of Genghis Khan disputed whether the royal line should follow from his son and initial heir Ögedei or from one of his other sons, such as Tolui, Chagatai, or Jochi.