Afro-Eurasia, Afroeurasia, or Eurafrasia, nicknamed the World Island, is a landmass which can be subdivided into Africa and Eurasia (which can be further subdivided into Asia and Europe). These three continents form the largest contiguous landmass on Earth. The terms are portmanteaus of the names of its constituent parts.
Afro-Eurasia encompasses 84,980,532 square kilometres (32,811,167 sq mi), a little over half the world's land area, and has a population of approximately 6 billion people, roughly 86% of the world population.
The following terms are used for similar concepts:
The oldest part of Afro-Eurasia is probably the Kaapvaal Craton, which together with Madagascar and parts of India and western Australia formed part of the first supercontinent Vaalbara or Ur around 3 billion years ago. It has made up parts of every supercontinent since. At the breakup of Pangaea around 200 million years ago, the North American and Eurasian Plates together formed Laurasia while the African Plate remained in Gondwana, from which the Indian Plate split off. This impacted southern Asia around 50 million years ago and began the formation of the Himalayas. (Around the same time, it also fused with the Australian Plate.) The Arabian Plate broke off of Africa around 30 million years ago and impacted the Iranian Plate between 19 and 12 million years ago, ultimately forming the Alborz and Zagros chains of Iranian Plate. After this initial connection of Afro-Eurasia, the Betic corridor along the Gibraltar Arc closed a little less than 6 million years ago, fusing Northwest Africa and Iberia together. This led to the nearly complete desiccation of the Mediterranean Basin, the Messinian salinity crisis. Eurasia and Africa were then again separated: the Zanclean Flood around 5.33 million years ago refilled the Mediterranean Sea through the Strait of Gibraltar and the Red Sea and Gulf of Suez Rifts further divided Africa from the Arabian Plate.