A discussion of potential astronomical role/status of Karnak: "Near the Nile River lies a temple complex called Karnak in what was once ancient Thebes and is now modern Luxor. The great Temple of Amun or Amen-Ra was a principal focus of Egyptian religious activity for millennia but what makes Karnak of particular interest is the controversy over its use.The British astronomer Sir Norman Lockyer visited the site around 1890 and was struck by an immense corridor that ran the length of the complex. Lockyer believed that it was aligned westward across the Nile River to the midsummer sunset around 4000 B.C. It was quickly pointed out, however, that hills across the Nile from the temple blocked out any view of the setting sun, throwing the theory into doubt. Another astronomer did some quick calculations and found that the corridor only matched up with the sunset in 11,700 B.C. Even the Egyptians were not building temples that far back in time". See the article for more.