Fortress of Babylon

The Fortress of Babylon sits behind a high, curved wall of layered limestone and brick, distinct from the surrounding city for its massive, circular towers. This Roman stronghold anchored the Nile frontier in the second century, controlling river traffic and the vital grain trade. When the Arab commander Amr ibn al-Aas arrived in the year six hundred and forty, his troops besieged this very gate for seven months. Its fall shifted the center of power from the Mediterranean coast to the site of Cairo.