Hominid dispersals in Europe refers to the colonisation of the European continent by various species of hominid, including hominins and archaic and modern humans. Short and repetitive migrations of archaic humans before 1 million years ago suggest that their residence in Europe was not permanent at the time. Colonisation of Europe in prehistory was not achieved in one immigrating wave, but instead through multiple dispersal events. Most of these instances in Eurasia were limited to 40th parallel north. Besides the findings from East Anglia, the first constant presence of humans in Europe begins 500,000–600,000 years ago. However, this presence was limited to western Europe, not reaching places like the Russian plains, until 200,000–300,000 years ago. The exception to this was discovered in East Anglia, England, where hominids briefly inhabited 700,000 years ago. Prior to arriving in Europe, the source of hominids appeared to be East Africa, where stone tools and hominid fossils are the most abundant and recorded. Arising in Europe at least 400,000 years ago, the Neanderthal hominids (a descendant of Homo heidelbergensis) would become more stable residents of the continent, until another descendant of H. heidelbergensis, H. sapiens, would arrive about 50,000 years ago, leading to the extinction of the Neanderthals about 37,000 years ago. Pre-human hominids In the early Miocene, Europe had a subtropical climate and was intermittently connected to Africa by land bridges. At the same time, Africa was becoming more arid, prompting the dispersal of its tropical fauna—including primates—north into Europe. Apes first appear in the European fossil record 17 million years ago with Griphopithecus. The closely related Kenyapithecus is also known from fossils in Germany, Slovakia and Turkey. Both Griphopithecus and Kenyapithecus are considered likely to be ancestral to the great apes. From 13 million to 9 million years ago, hominids flourished in Europe and underwent an adaptive radiation as they diversified in response to a gradually cooling climate. Middle Miocene European hominids include Pierolapithecus, Anoiapithecus, Dryopithecus, Hispanopithecus, and Rudapithecus. The diversity and early appearance of great apes in Europe has led some scientists to theorise that hominids in fact evolved there, before dispersing "back to Africa" in the Middle Miocene. Around 9 million years ago most of Europe's hominid species fell victim to the Vallesian crisis, an extinction event caused by the disappearance of the continent's forests. Some hominid species survived the event: Orepithecus, which became isolated in forest refugia; and Ouranopithecus, which