There are few ancient monuments more recognisable than the Sphinx - but is it as unique as it seems? The Histories & Mysteries website currently features an interesting story which asks whether there were actually two Sphinxes on the Giza Plateau. It begins by looking at the evidence for the more 'well-known' (though still 'heretical') claim that the Sphinx predated its supposed creator, the Old Kingdom pharaoh Khafre, such as the text found on the Dream Stele of Tuthmosis IV. It then reveals that a number of these ancient sources also discuss a second Sphinx:
What is particularly interesting on the Dream Stele of Tuthmosis IV is the representation of the Sphinx. There are two! Equally, one can see that the two Sphinxes sit on architectural constructions, i.e. a small temple with a gate. The usual interpretation from Egyptologists is that these temples are merely the representation of that what is present in front and to the South of the Sphinx. However, such a conclusion should fail to satisfy anyone, as it is well-known that the rules of perspective for the ancient Egyptians were very strict, and no official artist would allow himself to deviate from reality to such an extent.
Most importantly, in the Inventory Stele, there is mention of a lightning strike that struck the cap of a Second Sphinx, as well as a sycamore tree, a sacred tree in those days, which was burned by the same lightning strike. The lightning strike marked the beginning of the end of this Second Sphinx.
According to archaeologist Michael Poe, who refers to papyrus fragments from the Middle Kingdom, the Second Sphinx was located face to face with the still-existing Sphinx. It was located on the other side of the Nile, and was destroyed by a violent rising of the river Nile ca. 1000 AD. The local people took stones from the structure to rebuild their villages.
The article ends on a tantalising note, regarding the silence that surrounds this particular hypothesis ("Perhaps...because these Sphinxes hide something that gains access to something underneath the Gizeh plateau?"). Plenty in there to get Zahi's blood a'boiling, so enjoy.