The Kettensteg Kettensteg , a 68m long pedestrian bridge, was built right in front of the Fronveste in 1824, which makes it the oldest preserved iron suspension bridge in continental Europe. The bridge, constructed by the engineer Conrad Georg Kuppler, was built in four months time and replaced a wooden runway as Germany's first suspended bridge. Approximately 3,65 tons of low carbon steel were used during the building process. Its name derives from the three metres long chains on which the bridge is suspended at three, five metres high pylons. Massive abutments fix the bridge at the two banks of the river. Because of its span of 33m the bridge was deemed unsafe as the Kettensteg was vulnerable relating to vibrations, which lead to the bridge being stabilized in 1930. During the time of the National Socialism the bridge was marked for demolition as it did not fit into the historical townscape, however, the outbreak of World War II prevented the ordered demolition. The bridge was closed due to security reasons in 2009, restored and in 2010 again opened for pedestrian traffic.