The C18 rediscovery/ re-invention of concrete . . . it had apparently been made by the Romans, Greeks and Egyptians [–> earlier, the Nabataeans] (and many natural, volcanic or sedimentary rocks are concrete-like) . . . opened up a world of new building possibilities; especially, when it is reinforced by steel. As, we can see all around us. But, concrete here uses a high energy process based on limestone, so how can we break through such barriers for the Moon or Mars? And, how could this be relevant to our home world, Earth? We could look at bones and teeth. For: >>The minerals found in human teeth and bones that give them their hardness and strength belong to a group Read More ›