<P> Philip Johan von Strahlenberg in 1725 was the first to depart from the classical Don boundary by drawing the line along the Volga, following the Volga north until the Samara Bend, along Obshchy Syrt (the drainage divide between Volga and Ural) and then north along Ural Mountains . The mapmakers continued to differ on the boundary between the lower Don and Samara well into the 19th century . The 1745 atlas published by the Russian Academy of Sciences has the boundary follow the Don beyond Kalach as far as Serafimovich before cutting north towards Arkhangelsk, while other 18th - to 19th - century mapmakers such as John Cary followed Strahlenberg's prescription . To the south, the Kuma--Manych Depression was identified circa 1773 by a German naturalist, Peter Simon Pallas, as a valley that, once upon a time, connected the Black Sea and the Caspian Sea, and subsequently was proposed as a natural boundary between continents . </P> <P> By the mid-19th century, there were three main conventions, one following the Don, the Volga--Don Canal and the Volga, the other following the Kuma--Manych Depression to the Caspian and then the Ural River, and the third abandoning the Don altogether, following the Greater Caucasus watershed to the Caspian . The question was still treated as a "controversy" in geographical literature of the 1860s, with Douglas Freshfield advocating the Caucasus crest boundary as the "best possible", citing support from various "modern geographers". </P> <P> In Russia and the Soviet Union, the boundary along the Kuma--Manych Depression was the most commonly used as early as 1906 . In 1958, the Soviet Geographical Society formally recommended that the boundary between the Europe and Asia be drawn in textbooks from Baydaratskaya Bay, on the Kara Sea, along the eastern foot of Ural Mountains, then following the Ural River until the Mugodzhar Hills, and then the Emba River; and Kuma--Manych Depression, thus placing the Caucasus entirely in Asia and the Urals entirely in Europe . However, most geographers in the Soviet Union favoured the boundary along the Caucasus crest and this became the standard convention in the latter 20th century, although the Kuma--Manych boundary remained in use in some 20th - century maps . </P> <Table> Maps <Tr> <Th> Map </Th> <Th> Description </Th> </Tr> <Tr> <Td> </Td> <Td> Map of the world according to Anaximander (6th century BC). Only the parts of Europe, Asia and Africa directly adjacent to the Mediterranean and the Black Sea are known . The Phasis River of the Caucasus is imagined as separating Europe from Asia, while the Nile separates Asia from Africa (Libya). </Td> </Tr> <Tr> <Td> </Td> <Td> In this 1570 map of Asia (Asiae Nova Descriptio), the Tanais is used as continental boundary . Moscovia is represented as "transcontinental", having an Asiatic and a European part (labelled Europae pars). </Td> </Tr> <Tr> <Td> </Td> <Td> This 1719 map of "ancient Asia" (Asia Vetus) divides Sarmatia into Sarmatia Europea and Sarmatia Asiatica . The continental boundary is drawn along the Tanais (Don), the Volga and the Northern Dvina . </Td> </Tr> <Tr> <Td> </Td> <Td> Herman Moll (c. 1715) draws the boundary along the Don, the Volga, cutting across land from Samara to the Tobol River, following the lower Irtysh and finally the Ob River, placing Novaya Zemlya in Europe . </Td> </Tr> <Tr> <Td> </Td> <Td> A German map of 1730 by Johann Christoph Homann has a similar boundary to the one shown by Moll, but following the full length of the Samara bend and then cutting across to the Irtysh directly, placing the Tobol and Tobolsk in Asia . </Td> </Tr> <Tr> <Td> </Td> <Td> The "Academy Atlas" of the Russian Empire, published by The Saint Petersburg Academy of Sciences in 1745, draws the boundary along the Don, but then west of the Volga to Arkhangelsk </Td> </Tr> <Tr> <Td> </Td> <Td> 1803 Cedid Atlas (Ottoman Empire), draws the boundary along the Don, Volga and River Kama and then cuts northwards to Khaypudyr Bay . Novaya Zemlya is in Europe . </Td> </Tr> <Tr> <Td> </Td> <Td> 1806 map of Asia by John Cary, boundary along the Don and then the Volga until Samara, and north of Perm following the Urals, placing Novaya Zemlya in Asia . </Td> </Tr> <Tr> <Td> </Td> <Td> 1827 map by Anthony Finley, showing the boundary as running along the Don, the Volga, passing between Perm and Ufa, and running north over land to the Sea of Kara, placing Novaya Zemlya in Europe . </Td> </Tr> <Tr> <Td> <P> </P> </Td> <Td> 1861 map by A.J. Johnson, illustrating the modern convention, Caucasus crest, Ural River, Urals . </Td> </Tr> <Tr> <Td> </Td> <Td> 1914 map showing the boundary along the Manych River, placing Stavropol Krai in Asia </Td> </Tr> <Tr> <Td> </Td> <Td> Miles Clark in his 1992 "circumnavigation of Europe" followed the White Sea--Baltic Canal until Lake Onega and the Volga--Baltic Waterway to the Rybinsk Reservoir before joining the classical boundary along the Volga and Don rivers . </Td> </Tr> </Table>

What is the traditional dividing line between europe and asia