Ochsenpferchbunker, High-rise air-raid shelter in Neckarstadt-West, Mannheim, Germany

The Ochsenpferchbunker is Mannheim's largest above-ground bunker, standing at the northern Neckar bank by the Jungbusch Bridge approach. Its reinforced-concrete shell encloses 29,310 cubic metres over a 6,100-square-metre footprint, with a basement, ground floor and four upper storeys; walls are 1.10 metres thick and ceilings 1.40 metres. Two glass storeys were added on top in 2016.

The bunker was excavated in late 1940 and its shell built from April 1941 to January 1943, using forced laborers and over 10,000 cubic meters of reinforced concrete. During the first air raids on Neckarstadt on 9/10 May 1941 it was still under construction. In the night of 23/24 September 1943 a 10-hundredweight mine bomb hit the eastern stair tower without breaching it; further raids, including 26 August 1944, caused no serious damage.

Since March 2018 the bunker has housed Marchivum, Mannheim's house of city history and memory, after the city archive moved in from the Technical Town Hall. It holds the permanent exhibition "Typisch Mannheim" on local history, the NS exhibition "Was hat das mit mir zu tun?" and an NS documentation centre. The name Marchivum replaced Stadtarchiv Mannheim on 1 March 2018.

The Marchivum occupies the converted bunker; the reading room and exhibitions are reached through the building's entrance on Bürgermeister-Fuchs-Straße near the Jungbuschbrücke approach. Two glass storeys were added on top during the 2016–2018 conversion, while the historic bunker levels below keep their thick walls and narrow stair towers.

The bunker's name comes from the Ochsenpferch, the old field name of the plot where it was built; earlier it was also called Bunker an der Hindenburg-Brücke or Bunker Bürgermeister-Fuchs-Straße. Its eastern stair tower took a direct hit from a 10-Zentner mine bomb in the night of 23/24 September 1943 and held.