Impressed by the size of the ramparts of Tiryns, the Greeks thought they must have been the work of the Cyclops. It is still not known how mere men were able to lift such enormous blocks of stone, some of which weigh over 13 tonnes. Neither is it known how they assembled them to creates this 8 to 10m-wide wall perched on a hill. It is true that the project, started c 1400 BC, lasted for almost two centuries.