The bridge over the Little Belt strait was one of the engineering miracles of the interwar years when it opened in 1935. It was designed by the Danish State Railways' (DSB) chief bridge engineer, Anker Engelund. Cast in concrete with a self-supporting steel superstructure, the 1.1 kilometre long bridge was Denmark's greatest engineering work to date. With some difficulty, Parliament had managed to ensure that the bridge had two lanes. The bridge's two railways tracks still carry Funen-Jutland rail traffic. In connection with the H-shaped motorway network, a new, six-lane suspension bridge opened in 1970. But on this bridge there was no room for railway tracks and the six lanes are often congested.
The supporting structures for the Little Belt Bridge posed challenges for the engineer. In 1932, four piers had to be cast in situ in the strait. Four large floating caissons were cast, sailed out and tipped over the side of a boat to settle on the bottom. They had first to be buried, but they sank further and faster than calculated in the unstable clay on the bottom. One of the caissons went askew into the water and drifted off from the deposition site. Afterwards the caissons were fixed in place with long steel tubes hammered into the bottom. The piers could then be cast and the steel superstructure and struts mounted on top. The bridge is still in use as a road-rail bridge.