Autobahnbrücke Siebenlehn, Girder bridge in Nossen, Germany

The Autobahnbrücke Siebenlehn is a 413-metre hollow-box girder bridge carrying the A4 motorway over the Freiberger Mulde valley near Siebenlehn. Its deck rests on two continuous riveted steel plate girders 4.5 metres deep and 402.90 metres long, supported by five piers and two abutments. The main span measures 81.60 metres, and the piers are faced with reddish Meissen granite.

Construction began in September 1935 and was completed by November 1936, using red Meissen granite as structural elements. It was built as part of the motorway expansion connecting Dresden to Chemnitz.

The bridge represents a notable engineering achievement of the 20th century, displaying red Meissen granite pillars that cross the valley. Visitors can observe the craftsmanship of regional materials in its support structures.

The bridge carries the A4 between Dresden and Chemnitz near Siebenlehn. A vaulted tunnel runs through the western abutment, and an observation platform was planned at the southern valley edge. The bridge can be viewed from the valley below, where the Freiberger Mulde flows.

On 5 May 1945, three days before the war ended, German soldiers placed charges in a hollow built into pier III during construction. The spot was marked in the granite facing by a stone bearing the letter "U". The bridge survived; the charges were not detonated.