Siljan Ring Siljan Ring The Siljan Ring () is a prehistoric impact crater in Dalarna, central Sweden. It is one of the 15 largest known impact craters on Earth and the largest in Europe, with a diameter of about . The impact that created the Siljan Ring occurred when a meteorite collided with the Earth's surface during the Devonian period, about 376.8 ± 1.7 Ma. This coincides around the first Devonian extinction, the Kellwasser Event or Late Frasnian extinction at 376.1 Ma ± 1.6 Ma. The effects of the impact can clearly be seen in the bedrock in the area. The Cambrian,
Trans-European Airport network Trans-European Airport network The Trans-European Airport network is one of a number of the Trans-European Transport Networks (TEN-T) of the European Union. According to Article 13 of the Decision No 1692/96/EC of the European Parliament and of the Council of 23 July 1996 on Community guidelines for the development of the trans-European transport network, the Trans-European Airport network comprises airports situated within the territory of the Community which are open to commercial air traffic. Similarly to the seaports included in the Trans-European Transport network, the airports must correspond to one of the following three categories of connecting points: A. International