Creating a concrete structure involves extracting limestone from a quarry, heating it to 1450°C in a kiln and then grinding the residue to a powder to make cement. This cement is mixed with aggregates and water and poured into shuttering, which workers have spent hours painstakingly putting together along with rebar to give the structure its tensile strength. Once set, the shuttering is removed and, 28 days later, the concrete will have reached its full strength.

Why not cut out all this faff simply by using quarried limestone blocks to create the structure? After all, that is what people did for thousands of years before cement was invented. And stone is typically two and half times stronger, with a carbon footprint one third that of concrete.