Dagestani types, between 1905 and 1915. Dagestani couple posed outdoors for a portrait. A couple in traditional dress poses for a portrait in the mountainous interior region of Gunib on the north slope of the Caucasus Mountains in what is today the Dagestan Republic of the Russian Federation. Russian chemist and photographer Sergey Prokudin-Gorsky (1863-1944) was a pioneer in colour photography which he used to document early 20th-century Russia and her empire, including the vanishing way of life of tribal peoples along the Silk Route in Central Asia. In a railway-carriage darkroom provided by Czar Nicholas II, Prokudin-Gorsky used the three-colour photography process to record traditional costumes and occupations, churches and mosques - many now Unesco World Heritage sites - as well as modernisation in agriculture, industry and transport.