St Petersburg, founded in 1703 and now the second largest city in Russia, has always been considered as a ‘new city’. However, it was not founded on a barren site. The land in the mouth of the Neva has been inhabited since the Neolithic era. In the middle ages, it was home to Ingrian and Russian settlements. Constant military conflicts over this territory both in the Middle Ages and in post-medieval times have left their traces—the remnants of the demolished Swedish fortresses, Landskrona (fourteenth century) and Nyenschantz (seventeenth century). During the 300-year history of St Petersburg, many fortifications, engineering structures, and architectural sites have been lost, and their history and remnants are becoming a target for thorough architectural research.