Aswan Low Dam
In 1902, the Aswan Low Dam was completed on the Nile River by the British. This threatened to submerge many ancient landmarks, including the temple complex of Philae. The height of the dam was raised twice, from 1907–1912 and from 1929–1934, and the island of Philae was nearly always flooded. In fact, the only times that the complex was not underwater was when the dam's sluices were open from July to October.