They used the blood of the children they killed to mix with cement.
The incorporation of blood makes the cement very brittle. It’s been done since Roman times.
Basically a chemical reaction would occur with the other ingredients that turn the blood (and fat) into soap. This would create air pockets in the concrete, allowing the concrete to expand and contract without cracking when the temperature changed.
We surmised that this is one way they get rid of the evidence that they’ve sacrificed humans, but in higher concentrations. We surmised that we are building bridges and buildings with faulty foreign cement. Twin towers?
ThankQ for the refresher.
Ugh.