Two Of Scandinavia's Most Iconic Cities Are Linked By A Mind-Boggling Undersea Tunnel And Scenic Bridge

Copenhagen, Denmark, is a European paradise that is often voted the world's happiest city thanks to its bike lanes, green spaces, and 37-hour workweek. The city is also known for its innovative technology, and nowhere is this more evident than Øresund Bridge, which connects Copenhagen to the Swedish city of Malmö across the beautiful Øresund Strait. Øresund Bridge consists of two levels — one for cars, one for trains — and crosses over the sound for 5 miles (8 km) before becoming a tunnel on Peberholm island. At the end of the tunnel, the road pops out on the island of Amager, home to part of Copenhagen and its airport. 

A feat of engineering from the start, the bridge ultimately required the creation of a tunnel, along with an artificial island, now known as Peberholm. This was designed to avoid traffic issues with the nearby airport and to protect marine wildlife as much as possible. The Drogden Tunnel was originally built in several different sections before being put back together on the seafloor in "a game of massive underwater Tetris." (via ZME Science)

The toll bridge was created to connect Denmark and Sweden, and to connect the roads and railroads of Scandinavia with the rest of Europe. Opened in 2000 (three months ahead of schedule, despite the unfortunate discovery during construction of unexploded bombs from World War II along the seafloor, causing understandable delays), the Øresundsbroen — or Öresundsbron, depending on the country — symbolizes international cooperation, as Denmark and Sweden operate it together. While this soaring bridge that disappears onto an island is undeniably impressive, it's also relatively short, covering less than 10 miles (15.9 km). Yet, in the 25 years since it opened, it's had surprising impacts on both countries. 

Both Copenhagen and Mälmo, a Swedish melting pot and one of Scandinavia's most eclectic cities, have felt the economic impacts of this Øresund Bridge. Swedes can now more easily access jobs in the booming Danish economy, and although most commuter traffic is going to Denmark rather than Sweden, nearly 10,000 Danes now own summer homes in Sweden (around 11,000 Swedish summer homes are now owned by Germans, who can access southern Sweden much more easily via the bridge as well). Danes (and Germans) are attracted by the gorgeous, comparatively rural scenery, and generally lower prices for homes, around Mälmo in the Swedish province of Skåne.

As the engineers of the bridge built with nature in mind, scientists have been interested in the environmental impacts of the Øresundsbroen. One surprising result of the bridge happened on the artificial island of Peberholm, created to mark the transition from bridge to tunnel. Peberholm was created with natural material dredged from the ocean floor, and was planted with only a select few native plants. Only biologists can visit the island (outside of their cars), and, as the island was left to grow as it would, it's become something of a wildlife refuge, to everyone's surprise. Peberholm is now home to over 500 species of plants, and is a breeding ground for several gulls and the rare green toads. As the years pass, more birds and more bird species have claimed the island for themselves, and scientists continue to study this intriguing phenomenon.

The Øresund Bridge has been an exercise in international cooperation, multinational economics, engineering, and eco-conscious living for the last 25 years; what will the next 25 hold for this innovative bridge? Only time will tell.