Is that graphic accurate?
No, it is not. :’) It’s a pretty cool graphic though, actually three separate ones, it used to be on a now-defunct website in the late 1990s, and turned up again.
The “Campbell’s Tomb”, which is a never-used burial shaft of New Kingdom date, located as shown, on the plateau, behind the rump of the Sphinx, is in fact there. The rest of that underground stuff must be imaginary.
There’s some interesting claims made by Pharaoh Thutmose IV on the Dream Stele, which still stands propped between the front paws of the Sphinx — it says that upon clearing the sand (again, during New Kingdom times), the Sphinx was found to be located atop a door that led somewhere important, located under the statue. The only problem that can be seen with this is that most of the Sphinx is part of the surrounding strata, i.e., it was carved in situ from the limestone bedrock.
On the left butt cheek of the Sphinx (the beast’s left is on the right side if you’re facing the statue face to face) there’s a now-plugged hole, apparently dug by treasure seekers; the rough, meandering passage leads up toward the head of the critter, and also curlicues down into the bedrock, and it’s a dead-end both ways. Since the enclosure fills up with sand rather quickly, and Herodotus doesn’t mention the Sphinx at all, it’s likely to have remained covered with sand (there’s no literary reference to any clearings of the sand between Thutmose IV and the early 20th century) for over 2400 years, meaning that the robber’s hole was probably excavated during a fairly narrow period of time during Pharaonic times; the other possibility is, the Sphinx was cleared of sand during the time of the caliph who took so much interest in the Giza monuments, and it was his employees who dug into the statue.
Whoops, a bit of a slip — Campbell’s Tomb did have at least one sarcophagus in it, 7th c BC date.
http://images.nypl.org/index.php?id=1527243&t=w
http://www.davidpbillington.net/campbellstomb.jpg
http://www.1902encyclopedia.com/A/ARC/architecture-010.html
http://www.1902encyclopedia.com/A/ARC/architecture-fig22.jpg
http://www.1902encyclopedia.com/A/ARC/architecture-fig21.jpg
