The lecture will examine St. Petersburg's places of detention as important urban stories - from the Peter and Paul Fortress to 'The Crosses', the Lithuanian Castle, and 'The Bottle' of New Holland. St. Petersburg is often viewed through its palaces, canals, grand facades, and industrial quarters, but the city has another architectural story - buildings created for control, isolation, and strict order. Prisons tell much about the time, power, engineering solutions, and societal perceptions of punishment. Listeners will learn how the Peter and Paul Fortress became associated with a prison, who actually lived in the Lithuanian Castle, and why the famous 'Crosses' still evoke lively interest - especially against the backdrop of discussions about their future as an open public space. The lecture will be conducted by Alexander Kizik - an engineer, local historian, and guide for the project 'St. Petersburg Through the Eyes of an Engineer'. We share on our website where to go in St. Petersburg.