There has always been speculation about the technological prowess of ancient civilisations, and whether they were more advanced than is generally believed. The evidence is often fragmentary and controversial – a scrap of corroded alloy, or the remains of an ambiguous artefact, like the Baghdad battery 1 and the Antikythera mechanism. 2 But in one case the evidence is solid, substantial – and if one researcher is correct – gigantic.

The term ‘cement’ dates back to the Latin ‘cæmentium’, meaning rough stone. The Romans found that crushed rock mixed with burnt lime and water formed a mixture which hardened to a stone-like consistency.