Behind the grand halls, staircases, and archive doors, the fates of the owners, architectural details, and the 90-year history of the institution emerge. Participants will see how ancient interiors coexist with multimedia halls, coworking spaces, and closed collections. In 2026, the Central Library named after Lermontov will celebrate its 90th anniversary, and the jubilee becomes an occasion to view the building on Liteiny Avenue from an unexpected perspective. The route will pass through the mansion of the Musins-Pushkins - a house where the architectural memory of old St. Petersburg coexists with modern library life. Participants will start with the history of the building: they will learn about its design, the first owners, the fates of people connected to the house, and details that escape notice during a regular visit. Next, the walk will transport guests from the past to the present day. The library will show how historical interiors continue to function in the 21st century: multimedia halls, coworking spaces, and open digital areas have emerged here. A separate part of the route is related to what is usually hidden from visitors. Participants will be able to peek into closed collections and get acquainted with archival publications. Where to go in St. Petersburg can be found on our website.