History of Finland between 4000 BC - 1501 BC
Around 5300 BCE, - probably - pottery was present in Finland. The earliest samples belong to the Comb Ceramic Cultures, known for their distinctive decorating patterns. This marks the beginning of the neolithic period for Finland, although the subsistence was still based on hunting and fishing. Extensive networks of exchange existed across Finland and Northeastern Europe during the 5th millennium BCE. For example, flint from Scandinavia and Valdai Hills, amber from Scandinavia and the Baltic region and slate from Scandinavia and Lake Onega found their ways into the Finnish archeological sites undes excavatons today and asbestos and soap stone from e.g. the area of Saimaa spread outside of Finland. Rock paintings - apparently related to shamanistic and totemistic belief systems - have been found, especially in Eastern Finland, e.g. Astuvansalmi.
From 3200 BCE onwards, either immigrants or a strong cultural influence from south of the Gulf of Finland settled in Southwestern Finland. This culture was a part of the European Battle Axe cultures, which have often been associated with the movement of the Indo-European speakers. The Battle-Axe - or Cord Ceramic - culture seems to have practiced agriculture and animal husbandry outside of Finland, but the earliest confirmed traces of agriculture in Finland date later, approximately to the 2nd millennium BCE. Further inland, the societies retained their hunting-gathering lifestyles for the time being. The Battle axe and the Comb Ceramic cultures merged, giving rise to the Kiukainen culture which existed between 2300 BCE and 1500 BCE, featuring fundamentally a comb ceramic tradition with cord ceramic characteristics.
Reference: Wikipedia
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.