Database: Gates of Baghdad
From its foundation, Baghdad was surrounded by walls which protected its inhabitants against invaders and sandstorms. A series of large gates allowed military, processional, and commercial transit through these impressive fortifications.
The city's most striking feature was its round layout. This circular design was inspired by newer cities founded in the seventh century and by ancient cities like Gur or Veh-Ardashir founded by Sasanian kings, centuries before Caliph al-Mansur created Baghdad. By the tenth century, Baghdad had outgrown the original "Round City" and it was abandoned. Because of the destruction of the city by the Mongols in 1258 and the subsequent urbanistic development on top of the ruins, no archaeological evidence of it remains.
The circular inner city could be accessed through four equidistant gates. Each led to a different region or city of the empire and took its name from its destination: Kufa to the Southwest, Basra to the Southeast, Khurasan (Eastern Iran and Uzbekistan) to the Northeast, and Sham (Syria) to the Northwest. Many more gates dotted the outside wall. Most took their name from a feature or an activity performed in the vicinity, like a pomegranate market or a mill. Some were known for famous events that they hosted: as in other cities of the empire, the Iron Gate was thus called because it served as the gibbet on which the heads of traitors were displayed as a warning to others, most famously Caliph al-Amin's head (r. 809-813) after his defeat in a civil war.