title: Databases of visual sources in the Internet: problems of heuristics (based on the example of studying the history of the Southern coast of Crimea in the early XX century)
abstract: The article analyzes the experience gained by the author in the course of working with three online databases of visual historical sources in the context of studying the transformation of the Southern Coast of Crimea in the late XIX - early XX centuries. They are: the electronic State Catalog of the Museum Fund of the Russian Federation, as well as two crowdsourcing platforms - Pastview and Retromap.ru . The author examines the origin, format, structure of these aggregators of visual historical 
journal: Историческая информатика