Valley of the Kings rains. There is currently little year-round rain in this part of Egypt, but there are occasional flash floods that hit the valley, dumping tons of debris into the open tombs. The quality of the rock in the Valley is inconsistent, ranging from finely-grained to coarse stone, the latter with the potential to be structurally unsound. The occasional layer of shale also caused construction and conservation difficulties, as this rock expands in the presence of water, forcing apart the stone surrounding it. It is thought that some tombs were altered in shape and size depending on the types of rock the
Valley of the Kings unknown) were probably in the Seventeenth Dynasty necropolis of Dra' Abu el-Naga'. The first royal tombs in the valley were those of Amenhotep I (although this identification is also disputed), and Thutmose I, whose advisor, Ineni, notes in his tomb that he advised the king to place his tomb in the desolate valley (the identity of this actual tomb is unclear, but it is probably KV20 or KV38). The Valley was used for primary burials from approximately 1539 BC to 1075 BC. It contains at least 63 tombs, beginning with Thutmose I (or possibly earlier, during the reign of Amenhotep