Ernst Cohn-Wiener, an eminent art historian in Berlin in the 1920's, photographed the architecture of West Turkestan during two research expeditions in 1924 and 1925. The British Museum acquired the Ernst Cohn-Wiener Photographic Archive from the School of Oriental and African Studies of the University of London in 1998 where it had been kept as part of the Corpus Inscriptionum Iranicarum. The archive consists of 324 film negatives and 567 glass negatives. The photographs are essential for the study of architecture in the historic cities of Uzbekistan, Turkmenistan, Kazakhstan and Kyrgyzstan, as some of the buildings photographed are no longer extant, while others were over-restored during the Soviet era. Nearly seven hundred of these photographs are available on Archnet.