The city was largely destroyed during the Persian invasion of 525 BC
Ptolemaic Period - Its schools of philosophy and astronomy wholly lost importance after the founding of Alexandria in 332 BC
The monuments were plundered extensively, and used as a quarry for many building projects
When Strabo visited the site in the first century BC, he found it abandoned.
Nothing today remains of what must have been this important city and its cult center of the sun-god Ra. The form and size of the site's religious structures and even the main temple of the sun god are thus unknown, but it is possible that the solar temples of the 5th Dynasty, of which we have evidence at Abu Ghurob and Abusir, were modeled at least to some extent on the Heliopolitan sun temple,
with its central feature of the obelisk.
Earlier structures include the Third Dynasty fragmentary shrine of Zoser, of which only fragments now survive. Two of these fragments bear the name of Netjerikhet,
and another shows the Pharaoh seated with the ladies of his family gathered at his feet.
Today the only standing monument is a large red graniteobelisk called Cleopatra's Needles. It was erected by Senusret 1 from the twelfth Dynasty.
The remains of mud-brick walls in the area of Tell Hisn suggest a vast enclosure of 1200 by 500 meters, containing parts of a great temple of the New Kingdom, devoted to Ra, the precise shape of which is uncertain.