The "Abu Simbel Salvage Operation" was one of the results of the appeal of UNESCO to all its member states to help to rescue the monuments of Nubia threatened by the building of the new dam at Aswan. The protection of the temples at Abu Simbel, cut in the living rock, presented considerable technical difficulties. Several projects were considered; that which was finally chosen consisted of dismantling the temple facades and the walls of their rooms by cutting them into large blocks, removing these, and rebuilding the temples inside concrete dome-shaped structures in a simulated environment. A cofferdam had to be bult while the dismantling operation was in progress because of the already rising water of Lake Nasser. The whole huge Lego game was successfully completed, and the re-sited temples were reopened officially on September 22, 1968.