How large was Baghdad?

At its peak during the 8th to 13th centuries, particularly during the Abbasid Caliphate, Baghdad was one of the largest cities in the world, with an estimated population of over a million residents. The city spanned approximately 100 square miles, featuring a circular design centered around the Grand Mosque and the Caliph's palace. It was a major cultural, commercial, and intellectual hub, renowned for its wealth and influence. However, its size and population declined significantly after the Mongol invasion in 1258.