This bridge turns into an underwater tunnel, connecting two different countries together – Denmark and Sweden. This is the Øresund Bridge, an 5 mile long, double tracked (motorway and railway) bridge that connects Denmark and Sweden together via the Øresund strait.
One of the most amazing architectural feats of this bridge is that one end of it turns into a 2.5-mile underwater tunnel called the Drogden Tunnel. it was designed by the Danish architect George K.S. Rotne, cost about $5.2 billion dollars (US), and it is considered the longest combined road and rail bridge in Europe.