Käytävä Suomenlinnan muurien sisällä Käytävä Suomenlinnan muurien sisällä Share The walls of the fortress were hollow but several metres thick. They were able to withstand the round cannonballs of the 18th century well. Show on map Used in articles Turning Helsinki into a fortified city Article Article Go to content Photographer Helsinki City Museum / Ilari Järvinen Finna.fi record Open in Finna(Link leads to external service) Formats Image Photo Authors Järvinen Ilari Museokuva Copyrights CC BY 4.0 Buildings Helsinki City Museum
