On 3 March 2009 the Historical Archive of the City of Cologne collapsed into the pit of a new subway station. Two young residents died. A court-appointed expert found the cause in a defect, a Fehlstelle, in an underground concrete wall. In 2005 workers had left a block of rock in the excavation. According to the indictment, they dug on anstatt das Hindernis zu melden, instead of reporting the obstacle. The criminal courts then examined each person’s duty of care one by one. Two construction managers were acquitted in 2018. The court found breaches of their duty of care but held that these had not caused the collapse. A senior site manager received one year on probation in 2019. The judge said the eindeutige Warnsignale, clear warning signs, in a construction record should have led him to check more closely. The Federal Court of Justice overturned the judgments in 2021. In 2024 the court provisionally closed the cases against the four remaining defendants, against payments of money. In 2020 the construction consortium agreed to pay the city 600 million euros. At the time, it still disputed the cause.