The diversity of Roman institutions required a wide range of specialized buildings, some religious, others secular. There were commercial, domestic and recreational buildings; some were for entertainment and others purely utilitarian; there were honorific buildings such as triumphal arches, and of course a wide range of military and defensive buildings. Many of these buildings had already achieved what might be termed their orthodox form by the time of Augustus. Others, notably baths, still had a good deal of development ahead of them. Some buildings, such as temples and basilicas, remained relatively unchanged in their layout after the time of Augustus, although in the late Empire they occasionally appeared in a striking new form. For example, Hadrian's Pantheon was a breathtakingly original version of a Roman temple. Some buildings were affected by fashion or the economic climate. For example, houses were radically modified because of changing economic conditions in Roman towns, and high-rise apartment blocks began to take the place of the old domus during the early Empire. Buildings such as amphitheaters and circuses were steadily improved as time went on. For example the spina of the circus was angled to allow more space for the chariots at the crucial beginning of the race, and amphitheaters began to be equipped with a complex underground system of cells, which allowed a large number of animals to appear in the arena simultaneously, thus increasing the tempo of the spectacle. While all these changes were going on, the Emperors themselves were planning their own great building programmes. It is easy to look at Roman architecture simply as a series of great imperial projects, but we must remember that the whole fabric of Roman architecture was at the same time undergoing a constant process of modification and change. All these factors combine to make Roman architecture the complex and intriguing subject it is. 1. THE COLOSSEUM The most famous, and most influential, of all amphitheaters in the roman world was the Flavian amphitheater in Rome, better known today as the Colosseum (Gabucci 2001; Lancaster 2005b; Welch 2007). This was a grand and monumental building of four stories, 52m high, standing on elliptical concrete foundations 12m deep. It was an astonishing feat of planning and engineering on an unprecedented scale. With outer dimensions of 188 x 156m and an arena measuring 80×54m. An estimated 100,000m 3 of travertine was used for the facade with 300 tons of iron to clamp the blocks together. An amazingly short construction time was made possible by the erection of a skeleton structure of travertine blocks that allowed many components to be worked on at the same time. A combination of materials was used: concrete, travertine, and tufa, which allowed architects to address the specific structural challenges inherent in its design. The vaulted substructures beneath the cavea comprised a series of passages, corridors, and staircases. The three outer arcades formed two outer, annular corridors 7m high covered by concrete barrel vaults. One further ring corridor closer to the arena was constructed of brick-faced concrete with a veneer of marble; this particularly grand passageway was used by those accessing the ringside seats set aside for the elite. These annular passages were intersected by the radial passages that accommodated staircases, superbly organized for ease and control of access.

Roman art and architecture is a combination of Etruscan, Greek, West Asia, Egyptian, and native art. However, roman art came into appear very slowly and late but it had a special survival. Initially, this art and architecture was under the influence of Etruscan architecture then was under the influence of Greek art. Architecture of this period was mostly interested in urbanization and urban planning. Temple architecture was not notified very much in building them, the plan and components were under the influence of Greek and Etruscan architecture. Building temple was not the central subject for Roman architects but their main topic in their work was summarized into constructing large and public buildings and monuments. Unlike Greeks, Romans needed more space inside temple. It should be noted that one of the major successes in roman architecture was discovering a new material which can be called concrete. Roman architect succeeded to resolve and provide interior spaces by enjoying co...

“The combination of arch and vault construction with bricks as form-work and concrete as bonding material enabled the roman’s to construct great buildings with large interior space.”