Found between Poznań and Gniezno, a trip to Ostrów Lednicki allows the opportunity to visit the Museum of the First Piasts – Poland’s largest open-air museum. Situated on an island, tourists get to wander around the 10th-century ruins of a castle and church once used by both Mieszko I and his son. Once connected to the mainland by a pair of bridges the fortress is thought to have played its part during in repelling the Czech invasion of 1038 and archaeological relics that have been recovered since include weaponry, cutlery and the skeleton of a fallen Czech warrior.