It aims at addressing the special regional development challenges of northern Europe. These include cold climatic conditions, long distances, wide disparities in standards of living, environmental challenges including problems with nuclear waste and wastewater management, and insufficient transport and border crossing facilities. The Northern Dimension is also intended to take advantage of the rich potential of the region, for example in terms of natural resources, economic dynamism, and a rich cultural heritage. Besides, the Northern Dimension also has the objectives of addressing the challenges arising from uneven regional development, and helping avoid the emergence of new dividing lines in Europe following EU enlargement. With the enlargement of the Union on 1 May 2004 to include Estonia, Latvia, Lithuania, and Poland, the importance of the Northern Dimension has increased considerably: eight EU Member States (Denmark, Germany, Poland, Lithuania, Latvia, Estonia, Finland, and Sweden) surround the Baltic Sea, and the EU's shared border with Russia has lengthened. Recent years have seen far-reaching changes in the geopolitical map of northern Europe. The Baltic States regained their independence in 1991. Finland and Sweden joined the EU in 1995, and Estonia, Latvia, Lithuania, and Poland in 2004. These events greatly increased the Northern and Baltic “presence” of the EU, and substantially lengthened the common border shared by the EU and the Russian Federation. It was imperative to address constructively the new challenges and opportunities which these changes created. The Northern Dimension as an important topic for EU policy was first recognized at the Luxembourg European Council in December 1997. In the years which followed, the concept became more concrete. The Vienna European Council in December 1998 adopted a Commission Communication on a "Northern Dimension for the policies of the Union". Six months later, in Cologne, the European Council adopted "Guidelines for the Implementation of the Northern Dimension". In November 1999, the Finnish EU Presidency held a Ministerial Conference on the Northern Dimension, where an Inventory of current activities under the Northern Dimension was adopted. The Helsinki European Council in December 1999 invited the Commission to prepare a Northern Dimension Action Plan, and the Feira European Council in June 2000 subsequently adopted this first "Action Plan for the Northern Dimension in the external and cross-border policies of the European Union, 2001-2003". In April 2001 the Swedish EU Presidency and the European Commission organised the 2nd Ministerial Conference on the Northern Dimension in Luxembourg. In June 2001, the Gothenburg European Council endorsed a "Full Report on Northern Dimension Policies" that, while taking stock of the activities undertaken to implement "the Feira Action Plan", also outlined ideas and proposals for the continuation of the Northern Dimension initiative.