"Great Soviet Encyclopedia (O)" is a publication that reflects the most complete picture of world culture, science, technology and other aspects of human knowledge. Each article of this encyclopedia provides detailed information about a particular concept, event or phenomenon. The history of the origin and basic information related to the subject of the description are disclosed. The publication consists of numerous volumes, in which a huge number of illustrations, diagrams, tables and graphs are collected, which help the reader to better understand the material. "Great Soviet Encyclopedia (O)" is a valuable source of knowledge for researching various spheres of human life and culture.