Esfahan's pigeon houses

In Esfahan region there were more than 3 thousand pigeon houses of which 300 have been preserved until today. Each of these cylindrical or conical towers could accommodate between 14 and 15 thousand birds that each year produced around 70 thousand kilograms of excrement. These were mixed with the ashes and the earth by the farmers of Esfahan to obtain the fertilizer which was then used also in the tanning industry and in the manufacture of cordite. Precisely for this reason at the time of the Shāh Abbās Safavide relatively heavy taxes were imposed on the pigeon houses. Some of Esfahān's most important pigeon houses are:
Pigeon house Imam Khomeini: the external façade of this tower was built with plaster and a mixture of straw and mud while the internal one is made of brick and always mixed with straw and mud. The height of this tower is 11 / 25 meters and the diameter of its large cylinder is 6 / 7 meters.
Piccionaia Gurat: this tower which is located in the village of Gurat, in the rural district Qahāb, central part of the province of Esfahān, has two cylinders, inside and outside of which the latter, for a greater resistance has been built a little more inclined; on its roof there are nine brick-worked turrets that make it easy for pigeons to enter, ventilation and lighting.
Piccionaia Radān: this tower which is located at 3 km southeast of Esfahān next to the channel of the village of Radān, is cylindrical. Its diameter is 13 / 3 meters and the height of its large cylinder is 10 / 2 meters.
Pigeon house Hezār Jarib: one of these towers is located at the University of Esfahān and the other south of Sheikh Sadugh Street. The height of the large cylinder of the University pigeon house is 13 / 3 meters and the height of the entire tower 16 / 7 meters. The Sheikh Sadugh tower is a complex of eight small cylinders around a large central cylinder. The height of the latter from the ground is 13 / 2 meters and its diameter 13 / 5.