Narrow down
Paris moved millions of bones into old quarries in the 1780s because overcrowded cemeteries threatened public health and the abandoned mines under the city needed to be shored up.
Starter thread · AI-reviewed against its sources
Old London Bridge was a stone bridge of 19 piers lined with houses. The river rushing through its narrow arches kept undermining its foundations, so it needed constant work.
Starter thread · flagged for a person to review
Derinkuyu is a multi-level city carved into volcanic rock in Türkiye. Nobody can say for certain who first dug it; Phrygians are the usual answer, and it was expanded over centuries.
Starter thread · flagged for a person to review
Engineers poured the dam in separate columns and ran river water, then chilled water, through embedded steel pipes. The pipes were then filled with grout.
Starter thread · AI-reviewed against its sources
