The high hill towering over Topolno is the remains of a defensive settlement built probably at the turn of the 10th and 11th centuries. The medieval stronghold protected the Vistula trade route connecting Pomerania with Greater Poland Region. Together with the strongholds in Świecie and Gruczno, it formed a complex of border watchtowers. After the death of Mieszko II (1034), when several districts, including Vistula Pomerania, were separated from the Polish state, the stronghold ceased to exist. Today, only a high, truncated hill has survived, which is called "Talerzyk" (“Little Plate”) due to its characteristic shape. A dirt road leads to its peak, surrounded by bushes and wild fruit trees. It is worth crossing it to enjoy the view of the beautiful panorama of the Vistula valley.