The Valley Temple was a level created for Tomb Raider: The Last Revelation but was ultimately dropped from the final game at some point in development. It was intended for the Giza section in between the Sphinx Complex and Underneath the Sphinx.
The level can still be found on the disc of the final version of the game under the name "joby1b.tr4". Joby Wood was the level designer of the Giza levels. It may have been removed in September 1999 or earlier considering that it features the earlier versions of the shotgun and flares.