cement

The History of Concrete and the Nabataeans:

Professor Dr. Joseph Davidovits is a recognized world expert on ancient cements and concretes. Much of the following material is taken from his website: http://www.geopolymer.org. Dr. Davidovits is …

Gryn:

Gryn is located in the southern highlands of Jordan, south of Ayl. On the hill-top stands a fortification, while the artesian wells empty their water into ancient cisterns and aqueducts below the …