Bornholm, Danmark
Next up was the island of Bornholm itself. First stop was Sankt Ols Church, one of Bornholm's four round churches. Built in granite in the 12th century, its stones are natural fieldstones. Like other round churches it has three storeys. The third storey shows traces of large openings and multiple arrow slits, suggesting that the church served as a stronghold in times of conflict. We then continued onto the fortress of Hammershus, the largest medieval fortification in Northern Europe and believed to have been built in the 13th century