In general Islamic civilization emphasized the harmony between man and nature as seen in the traditional design of Islamic cities. Maximum use was made of natural elements and forces, and men built in harmony with, not in opposition to nature. Some of the Muslim technological feats such as dams which have survived for over a millenium, domes which can withstand earthquakes, and steel which reveals incredible metallurgical know-how, attest to the exceptional attainment of Muslims in many fields of technology. In fact it was a vastly superior technology that first impressed the Crusaders in their unsuccessful attempt to capture the Holy Land and much of this technology was brought back by the Crusaders to the rest of Europe.