Today it is often repeated that Siberia is the heart of Russia. It took a lot of time to develop this region. Travelers for a long time and through hardships tried to unravel the secrets of Siberia.The cartographer Semyon Ulyanovich Remezov compiled the "Drawing Map of Siberia" in the 17th - early 18th centuries, but it did not help to fill all the gaps in the unknown area. There was so little information about Siberia that the number of questions significantly exceeded the number of answers.The academic detachment of the Second Kamchatka (Great Northern) Expedition, headed by Professor of the Academy of Sciences, historiographer Gerhard Friedrich Miller (1705-1783), helped us to learn about many riches, peoples and settlements of Siberia. The detachment began its journey from St. Petersburg, gradually moving along the planned route: Kazan, Yekaterinburg and Tobolsk. The detachment was able to reach the city of Omsk (one of the central cities of modern Siberia) by the Irtysh River. But at that time, scientists reached only the first Omsk fortress. Why was the study of this fortress important? It helped to understand why Omsk appeared on the map of Russia. We will start our acquaintance with the city from the very beginning!