There has been a fortified hill in Lieto (“Liedon Vanhalinna”) from the prehistoric age. According to excavations, the castle has been in use in the Late Bronze Age (1500-500 BC), in Middle Iron Age (500-700 AD, contested) and in the Middle Ages up to the end of the 14th century, when it was replaced by the "new castle" in Turku harbour.
During the first crusade (ca. 1155) to Finland Swedish army fought heavy battles against pagan Finnish people to conquer Lieto castle hill. After the victory Swedish fortified hill with stone and brick walls to defence the new city of Turku and christianity against Finnish and Novgorodians. There were several buildings, outer walls and a watch tower in the hill. When the Turku castle was completed Lieto castle lost the military value and was left to decay. The latest record of the existing castle date from the year 1438.
In the 1956 private landowners donated Lieto hill to the University of Turku, which has used hill for the archeological training. Nowadays there are some few ruins left of castle walls and buildings.
The Externsteine (Extern stones) is a distinctive sandstone rock formation located in the Teutoburg Forest, near the town of Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. Archaeological excavations have yielded some Upper Paleolithic stone tools dating to about 10,700 BC from 9,600 BC.
In a popular tradition going back to an idea proposed to Hermann Hamelmann in 1564, the Externsteine are identified as a sacred site of the pagan Saxons, and the location of the Irminsul (sacral pillar-like object in German paganism) idol reportedly destroyed by Charlemagne; there is however no archaeological evidence that would confirm the site's use during the relevant period.
The stones were used as the site of a hermitage in the Middle Ages, and by at least the high medieval period were the site of a Christian chapel. The Externsteine relief is a medieval depiction of the Descent from the Cross. It remains controversial whether the site was already used for Christian worship in the 8th to early 10th centuries.
The Externsteine gained prominence when Völkisch and nationalistic scholars took an interest in the late 19th and early 20th centuries. This interest peaked under the Nazi regime, when the Externsteine became a focus of nazi propaganda. Today, they remain a popular tourist destination and also continue to attract Neo-Pagans and Neo-Nazis.