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.
La Hougue Bie is a Neolithic ritual site which was in use around 3500 BC. Hougue is a Jèrriais/Norman language word meaning a \'mound\' and comes from the Old Norse word haugr. The site consists of 18.6m long passage chamber covered by a 12.2m high mound. The site was first excavated in 1925 by the Société Jersiaise. Fragments of twenty vase supports were found along with the scattered remains of at least eight individuals. Gravegoods, mostly pottery, were also present. At some time in the past, the site had evidently been entered and ransacked.
In Western Europe, it is one of the largest and best preserved passage graves and the most impressive and best preserved monument of Armorican Passage Grave group. Although they are termed \'passage graves\', they were ceremonial sites, whose function was more similar to churches or cathedrals, where burials were incidental.