of plan and elevation can also be mentioned. Through the ages these elements have recurred in completely different types of buildings, constructed for various programs and under the patronage of a long succession of rulers. The columned porch, or talar, seen in the rock-cut tombs near Persepolis, reappear in Sassanid temples, and in late Islamic times it was used as the portico of a palace or mosque, and adapted even to the architecture of roadside tea-houses. Similarly, the dome on four arches, so characteristic of Sassanid times, is a still to be found in many cemeteries and Imamzadehs across Iran today. The notion of earthly towers reaching up toward the sky to mingle with the divine towers of heaven lasted into the 19th century, while the interior court and pool, the angled entrance and extensive decoration are ancient, but still common, features of Iranian architecture. City design The circular city planning was a characteristic of several major Parthian and Sasanian cities, such as Hatra and Gor (Firuzabad). Another city design was based on a square geometry, found in the Eastern Iranian cities such as Bam and Zaranj. Pre-Islamic architecture of Persia The pre-Islamic styles draw on 3000 to 4000 years of architectural development from various civilizations of the Iranian plateau. The post-Islamic architecture of Iran in turn, draws ideas from its pre-Islamic predecessor, and has geometrical and repetitive forms, as well as surfaces that are richly decorated with glazed tiles, carved stucco, patterned brickwork, floral motifs, and calligraphy. Iran is recognized by UNESCO as being one of the cradles of civilization. Each of the periods of Elamites, Achaemenids, Parthians and Sassanids were creators of great architecture that, over the ages, spread far and wide far to other cultures. Although Iran has suffered its share of destruction, including Alexander The Great's decision to burn Persepolis, there are sufficient remains to form a picture of its classical architecture. The Achaemenids built on a grand scale. The artists and materials they used were brought in from practically all territories of what was then the largest state in the world. Pasargadae set the standard: its city was laid out in an extensive park with bridges, gardens, colonnaded palaces and open column pavilions. Pasargadae along with Susa and Persepolis expressed the authority of 'The King of Kings', the staircases of the latter recording in relief sculpture the vast extent of the imperial frontier. With the