Trans-Siberian Railway metal truss bridge on stone piers, over the Kama River near Perm, Ural Mountains Region, Russia, c1910. The rivers were only one of the natural barriers that the builders of the Trans-Siberian Railway had to conquer in the feat of constructing a railroad over 6,000 miles, from central European Russia eastward to the Pacific Ocean. 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.