In addition to the Egyptian Heliopolis, The Romans called another site Heliopolis, located in Baalbek, Lebanon. Interestingly, Baalbek/Heliopolis is also located at an azimuth of 45 degrees from Giza. Here is a google map image of the Great Pyramid with a path drawn from the apex of the pyramid to the temple at Baalbek:



Here is a google image of Baalbek:



Baalbek is approximately 406 miles from Giza. A Parthenon style building was built on top of the foundation at Baalbek, that was larger than the Parthenon in Greece, but it was dwarfed by the foundation it was built on. The foundation at Baalbek covers approximately 5 million square feet. The foundation was built with megalithic blocks, some in the range of 1000 tons each.