Ancient people knew

That people do not know the "Great Wall" quite well. Were Needless to say, is a typical structure of China has been registered as a World Heritage Site. And, interestingly, the people of ancient China, as a joint sealer build up when the stone, using a magnesium oxide is that you know what it is.

It has been said, thanks to its strength, and leave the original form is kept nearly the figure of several thousand years before the present day. People in those days, in spite of it has not been enough scientific validation, it was empirically not understood, an excellent job of magnesium oxide as a material for soil hardening.

The house is magnesium oxide, whether it was supporting an environment that suggests how human beings since ancient times, and was a very interesting case.