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 Queens tombs. The burials in the subsidiary valleys all date to the 18th dynasty. The reason for choosing the Valley of the Queens as a burial site is not known. The location in close proximity to the worker's village in Deir el-Medina and the Valley of the Kings may have been a factor. Another consideration may be the existence of a sacred grotto dedicated to Hathor at the entrance of the Valley. This grotto may be associated with rejuvenation for the dead. One of the first tombs to be made in the Valley of the Queens is the tomb of Princess