Database: Camels
While camels are a mandatory cliché of any depiction of the Islamic world, the so-called "desert ships" have long been not only an iconic but also a crucial means of transport across Eurasia.
Camels were already a well-known method of travel during antiquity, used from Morocco to China. Their wide padded feet helped them keep their balance on any path, while their fatty humps provided them with energy in regions where food was scarce. Moreover, the camels could eat almost any plant, even thorny ones, and turn them into milk or meat for hungry caravanners. They also showed great resistance to extreme temperatures, with dromedaries (one-hump) more desert-resistant and Bactrian camels (two-humps) more tolerant to cold and high altitudes. They could carry much heavier loads than horses or donkeys, making them perfect pack animals. Their efficienicy and flexibility had a clear effect on the economic wealth of the Abbasid empire, boosting its trade and facilitating travels all across its huge expanse. They were also useful in warfare, as they could run surprisingly fast!
The preferential use of camels had important consequences on the landscape and the city planning of the empire. Caliphs did not need to maintain an extensive paved road network, as camels did not need one. Since camels made wheeled carts virtually unnecessary, Abbasid cities could also maintain narrower roads. The tall buildings that lined these narrow roads kept the city in shade, meaning that the ambient temperature inside cities was several degrees lower than in surrounding open areas.