Germany: Medieval Plank Causeway Discovered under central Berlin street

Archaeologists from the Landesdenkmalamt Berlin (LDA) made a sensational find in January 2022 during their excavation at Molkenmarkt: about 2.50 m below Stralauer Straße, they came across a medieval plank embankment. It is the earliest fortification of Stralauer Straße from the medieval founding period of Berlin in the 13th century. Initial wood samples revealed a felling date of around 1238 (tree ring analysis).

The embankment was made of oak, pine and birch trunks. The elaborate wooden fortification of the road here near the Spree enabled safe passage from the Mühlendamm towards the Stralauer Tor over the very wet ground near the river. The stub embankment is extraordinarily well preserved, thanks to a thick layer of peat that covered the timbers airtight for over 700 years.

The reason for the archaeological work in preparation for construction is the laying of electricity and gas lines as part of the street reconstruction around Molkenmarkt in Berlin-Mitte, which is being carried out by the Senate Department for the Environment, Mobility and Climate Protection (SenUMVK).

The wooden structure consisting of three layers - slightly offset from the alignment of Stralauer Straße - has so far been detected over a length of at least 50 m. The width of the embankment is approx. 6 m. The top layer is made up of barked logs lying close together across the direction of travel.

They rest on three parallel rows of beams in the longitudinal direction of the embankment: at the edges and in the middle of the road cross-section. The substructure consists of thick, roughly worked logs. The two lower layers were already hidden invisibly under fill sand in the Middle Ages. Missing parts of the uppermost layer were filled in with field stones.

The archaeological investigations aim to precisely investigate the construction and extent of the road and to narrow down its age. All phases of the construction are being documented with modern technology. Due to the laying of the new electricity and gas lines, most of the medieval substance will be destroyed.