There are three main passages that cut though Denmark and one of them, the Øresund (or Öresund in Swedish) was earmarked as a crossing between Denmark and Sweden. The Swedish and Danish authorities agreed to construct a bridge across the strait in 1991. On the 14th August 1999 the connection was complete but the official opening wasn't until 1st July 2000. The opening ceremony was begun with a minutes silence after the tragedy at the Roskilde festival that saw 9 fans killed. As a result, crowd surfing was banned at many festivals in Europe.
The Øresund Bridge comprises of both a tunnel and a bridge. The bridge section had the longest cable mainstay in the world at 490m and carries both road on the top level and rail traffic below. The tunnel section at the western end of the link begins from an artificial island named Peberholm and is the longest immersed tube tunnel in the world at 4km. The tunnel of 20 sections that were constructed off site and then submerged. The water is then pumped out and the sections were then sealed. Each section was the largest ever built weighing a huge 55,000 tonnes each!
The artificial island, Peberholm, is now a haven for wildlife, uncontaminated from human presence. Biologists are allowed on the island just once a year and since 2007 over 400 hundred different species of plants have been found as well as thriving populations of beetles, spiders and birds call the island home.
The exact cost of the connection is unknown but it is likely to be around DKK 30 billion (£2.3 billion). The cost was split between both the Swedish and Danish governments and that by 2037 the whole project would have been paid for from tolls for the tunnel and bridge. It is estimated that by 2019 as many as 39,000 vehicles will use the crossing every day.