A hundred years ago, colour photography was in its infancy and 20 years from going mainstream.
But one innovator, Sergei Prokudin-Gorskii, was a Russian who travelled around Imperial Russia taking colour photographs to record a world that was about to be swept away by the Bolshevik Revolution.
Given special permission from the Tsar, Prokudin-Gorskii was able to travel to the furthermost corners of the Russian Empire and capture images never seen before.
Michel Soussaline is Prokudin-Gorskii's grandson. He spoke to Witness about his grandfather's photographs.
(Photos copyright Library of Congress / Famille Procoudine-Gorsky)
Witness: The stories of our times told by the people who were there.