The "fourth-generation Wall", known officially as "" (retaining wall element UL 12.11), was the final and most sophisticated version of the Wall. Begun in 1975 and completed about 1980, it was constructed from 45,000 separate sections of reinforced concrete, each high and wide, and cost DDM16,155,000 or about US$3,638,000. The concrete provisions added to this version of the Wall were done to prevent escapees from driving their cars through the barricades. At strategic points, the Wall was constructed to a somewhat weaker standard, so that East German and Soviet armored vehicles could easily break through in the event of war.