Heliopolis was supposed to have been Egypt’s largest city.

It was never discovered in Egypt, though.

It was a 17,000 year old burial center with 2 great pyramids, and a Wonder of the Ancient World, “the Labyrinth”, with 3,000 burial chambers, and its nearby man-made sea, Lake Moeris. p. 74

Heliopolis was Teotihuacan in Mexico.