'The architecture of the city summarizes the city's form, and from this form we can consider the city's problem.'- Aldo Rossi
Cities and their formation can be described in many different ways. Some sort to functionalism as a way to critique the formation of city, while others seek the historical value in formulating the city. Aldo Rossi takes a very different stand on describing the city. He describes the city primarily based on its form, its architecture  . The architecture of the city frames the way the city shapes itself. He further states that 'the city is a gigantic man-made object, a work of engineering and architecture that is large and complex and growing over time;'  . The complex nature of the city is the most difficult part to analysis and describe. Various layers go into the formation of the city. The architecture and the built environment are the visible forms of the city. In my essay, I would try to look at the various layers that go into the formation of the city. The varied forms of mobility within the city fabric and the ability of architecture to direct it or to neglect it is a case of major concern and study.
The architecture of the city showcases the permanence and the very existence of the city. Rossi puts this idea of formation of city in a way that the '...crucial aspects of the city are the urban artifacts, which like the city itself are characterized by their own history and thus by their own form.'  The city in terms of Rossi is the hybrid of its architecture along with its form and the permanence of the city's urban artifacts. At this point I would like to state how Rem Koolhaas' describes the city or more so Manhattan as a state of architecture which over many years and experiments forms a hybrid type that builds itself. The architecture of importance, in the form of the needle and the architecture of absorption, in the form of a globe correlates as a hybrid architecture of acceptance and impact. The form of the city here again is best illustrated by its architecture. Rossi and Koolhaas both give equal importance to the role of architecture in the formulation of the city. Koolhaas in his theory of Manhattanism (his manifesto for Manhattan, he as the ghost writer), terms 'Manhattanism as an urbanistic ideology that has fed, from its conception, on the splendours and miseries of the metropolitan condition-hyper density...'  the architectural interpretation of Manhattan as a place of experiments and hybridised environment of the locus and its impact on the city is best explained in Koolhaas theory. Here, I try to relate to Rossi's comment on the locus  , the value of place in urban architecture. The locus or the place in an urban fabric is best optimised in case of Manhattan, a place for future, a place of hybrid architecture.
Over many years of experimenting and fantasying in Coney Island, (an offshoot from Manhattan) the architecture of prominence - architecture of dominance and power, the skyscraper as a typology which best merges between the needle and globe phenomenon of both resonance and absorption. The architecture of resonance could be the term that best describes the architecture of Manhattan. The formation of a strong two dimensional grid system in the mid 1800's for Manhattan gave the freedom to experiment with the available three dimensional aspects. Koolhaas states that 'Manhattan's architecture is a paradigm for the exploitation of congestion. '  His statement on the architecture of Manhattan and Rossi's argument that the architecture and its form describe the city goes hand-in-hand in the argument that architecture has a major role in framing the fabric of the city, and also the character of the city. This puts immense pressure on the architecture and architects in framing the city. The permanence and the growth of a city are also linked to its architecture. Rossi states that the monuments in a city define permanence. He further adds that the monuments define 'persistences'  and mentions the importance of primary elements which form the basis of the city. The housing, fixed activities, and circulation  are three most principal functions within the city in terms of Rossi. The fixed activities could be classified as architecture of static such as stores, schools, commercial buildings, hospitals and so on  . The other force that binds the city together is the kinetic force of circulation and movement. The kinetics of the city drives the city forward. The static elements or fixed elements are part of the urban fabric and could be constant or permanent. I would not like to term static elements as elements that are not in motion, but these elements form the framework of a city, the skeleton around which the city develops. Without these elements there wouldn't exist- a city. Every architectural intervention has a sense of movement within it or around it. Some try to enhance it and some neglect it. In Manhattan the architecture of the vertical enhances and absorbs the kinetic into the architecture and dissolves it into the fabric. The flow of people is directed by the architecture and the intangible forces of the exteriors of architecture. The ability to direct people and the influence on the pattern of movement around the building is through the different elements of the architecture- the impression it has on the street it faces, the elevation and the facade. I would expand on this argument about the relation between the architecture and its influence on the kinetics and the street later on in the paper.
The city is not a single entity. Numerous layers go into formulating a city. Architecture and the people residing in the city form the basis of urbanism. The different layers of the architecture, the street patterns, the monuments and urban artifacts along with the constantly changing kinetics of the city-its people camouflage together to form the concept of the city. Koolhaas uses the term Schism'  to explain the various layers of planes that formulate the skyscrapers of Manhattan. Vertical Schism  is best portrayed in the skyscraper. The various layers disconnect from each other and create a different sense of urbanity- 'interior urbanity'  . The layers though within a single structure work independently in their different ways, but all these layers form together the concept of the skyscraper. Similarly various layers though varied, work in conjunction in framing the urbanity of a street, a block, a locus or the city as a whole. These layers, many of which are intangible complete the city. The urban architecture along with these different layers that overlay over each other characterize the city. To put in terms of the cubist paintings of Picasso  and Robert Delaunay  , the phenomenal transparency in the paintings gives us the opportunity to analysis architecture and its qualities in their opaque and transparent layers. The ambiguous layering leads to a unique formulation of planes and surfaces that correlate with each other and complete the picture. This in terms of urbanism and the city would give us a clear idea of the various layers and surfaces that coexist in relation to each other. These layers of different scales and magnitude work in conjunction to form the concept of a city. The layers of road networks, transportation systems, landscape, and the people all together with the built environment form the city.
Koolhaas emphasis the concept of 'a city within a city'  His ideology of the skyscraper as a typology that creates a complete interior urbanity emphasises this idea of a city created within a city. A new sense of place is inscribed into the city fabric- a place which disconnects from the exterior but at the same time works in conjunction with the exterior fabric of the city. The vertical schism creates a sense of displacement but at the same time accommodates the kinetics of the city-its people. The power to absorb and dissolve the kinetic into the city fabric lies in the architecture of the city. The question now arises of- Should architecture accommodate the kinetic? The kinetic aspects of the city as mentioned earlier could be intangible. The architecture of Manhattan, its skyscrapers has the ability to accommodate this theory. A pattern is derived. Each city, each locus has a particular pattern of exchange. These patterns are very difficult to decipher, but are very important to the structure of the city. The human nature of movement and needs are varied but architecture and the infrastructure has the ability to create patterns and modes of movement. The term Koolhaas uses to layer the skyscraper as schismatic gives us an idea of the true nature of the skyscraper as a building typology, the different layers stacked vertically creates this notion of displacement in terms of contextual relation but at the same time induces a sense of continuous movement and flow of kinetics within the building and the peripheral block around it. The kinetic aspects of the city are constantly in motion and changing dramatically over time, while the architecture is more or less static in form but the function changes as well over time. The architecture of Manhattan is an architecture that accommodates this theory of constant change.
This terminology of schismatic layering can be tested in the horizontal plane as well in the 2 dimensional aspect of the plan of the city. Within a city fabric various layers, some prominent while some others intangible and unusual bind the city together and gives the city its uniqueness, its character. These forces that run parallel to the urban artifact  (the primary elements that form the city) are the ones that create a sense of place within a space. These forces could be the infrastructural nodes, the street, and the hawkers on the street or even the diverse mix of people that keep moving from one place to the other. The continuous flow of energy within a space makes it active. There is a question that arises here whether each street should be active? Or each building has to serve the purpose to accommodate this theory? These questions arise automatically because of the nature in the way the city is framed. The theory of the city if framed on the basis of its architecture and its ability to complement the kinetic elements along with the theory that change is the only constant, the argument of the importance of architecture in framing the character of the urban area is made stronger. The urban areas within a city are differentiated by the different patterns of the street and the architecture. People attract people  . The city or more precisely its architecture-should it attract people? is a debatable concept. It is true that not all buildings would attract people. But the architecture has the ability to influence the movement patterns around an urban area.
Rossi mentions Poete's statement on the importance of the street in relationship to the city. He states that 'the city is born in a fixed place but the street gives it life.'  The street characterizes an urban area and the city on the whole and Poete mentions that the street has the capacity to characterize a geographic area, classifying it into different activities depending on the street pattern. In his argument he states that 'Streets, whether cultural or commercial, should also be able to be characterized according to the nature of the changes that are effected because of them.' 
The pattern of streets with their various layers of activities it supports- transportation networks, mobility, pedestrian patterns, squares and parks along the street, street furniture add to the character of the area. The functions of the buildings along the street edge determine the movement pattern as well. The street and the built environment along the street both work in correlation to determine the life on the street and the character of the place. Oxford Street in London is completely different when compared in function and character in relation to the parallel streets in Bloomsbury and Fitzrovia. The functions of the buildings in these streets could be determinant in framing the character of the street life, but these functions are never constant. Rossi criticises the naive classification of urban areas on the functional aspects alone. Though it is easier at this level to classify streets and the city on the basis of the function alone. There are many more layers that add on with the functions that define the architecture and the character. By defining the different values and attributes that go with the functional aspects a much clearer picture of the city is framed.  But for the purposes of this discussion on the difference in the street life, I sort to this classification based on the functionality of its architecture along with the different layers. Oxford Street with the multinational clothing stores along with a chain of restaurants and local shopping stores add to the continuous movement of people along the street and into the architecture as well. The flow of people is systemised and organised in a rhythmic linear pattern. The parallel streets like Newman Street and Percy Street depending on the functions in the built environment, mostly offices and residences change in the nature of street life it has to offer. The functions in these buildings along a street are not negligible. In Fitzrovia area of London, the multidimensional qualities of street life and different movement patterns- some streets with continuous influx of people, while some streets have a specific crowd of people it attracts is determined by the functions that happen along in the buildings that edge the streets. Charlotte Street with a multitude of restaurants and pubs has a different character of movement and life on the street and Gower Street with the University campuses has a complete linear movement of people-single dimensional. All these mixed uses functions and the mix of different activities gives a character to the street and the area overall. The quality of the streets may be attributed to the functions but this attribute of function is not constant. The quality of urban areas can be altered if necessary by altering the functions of the architecture. The architecture has the ability to accommodate this change.
The hierarchy of street life adds character to an area and depending on the activities in the buildings, similar local activities offshoots onto the streets. The presence of a cinema or a pub in the vicinity leads to a small hot-dog vendor on the street. These mutual relationships add life to the area and initiate the kinetic to drive the city forward. 'The crossroads are public squares'  This statement illustrates the power of the crossroads. For example, the Oxford circus crossroad junction acts as a public square, hundreds of people wait at the signal. With the architecture around the junction and the tube station at the periphery, the pattern of movement of people along with the food vendors creates a different street life all together at this junction- a public square is ignited. All these illustrations show the capability of a street to shape the character of the city.
Time as a factor along with the street life and the architecture is another aspect that frames the character of a city or region. Most places change their character as the time changes. If we look at the historical aspect of it, it is interesting in the way Rossi describes it. The example of the Palazzo della Ragione  in Padua, in where Rossi on a more macro level determines how the function kept changing over time while the form remained; a propelling monument  drives the city forward and merges into the fabric of the city. This could be used to understand the role of time and its impact on the architecture and the form of a place. There exists another notion of time which is more kinetic which relates to the earlier discussion of streets and its role. Over a period of a day the street life keeps fluctuating depending on the surrounding built environment and the flow of people. New layers of activities keep adding or reduce as the day progresses. For example Kothawal Chawadi- (a market area in Chennai) adds on multiple activities in the day. It is a market for wholesale fruits and vegetables in the early hours using the street for the stalls, midday it turns into a more organised wholesale market for food grains and during the night it acts as food stalls attracting people throughout the day and night. The area is vibrant with such activities of different scales and magnitude. This multiple layers of activities bind the fabric together and give a unique character to a place. Similar characterizing elements are found in the markets of Spitalfield, and different borough markets in London. These street markets add life to the street and are integral parts in formulating the spatial character of the area. The multitude of functions and the ability to transform are part of the city fabric.
Rossi mentions Lavedan's theory on the origins of the city as "whether it is a matter of a spontaneous city or a planned city, the trace of its plan, the design of its streets, is not due to chance. There is obedience to rules, whether unconscious in the first case or conscious and open in the second. There always exists the generating element of the plan." 
The plan of the city is rooted in its history and a directive pattern could be traced from the layout of streets and the monuments present in the city. Rossi in his theory mentions the importance of the primary elements and the monuments in the forming of a city; both strongly interrelated to characterize the city. The monuments with its strong character and impact on the city along with the urban artifacts are permanent elements in a city. The plan of the city which in turn relates to the architecture and the primary elements- the street one of them, form the persistent characters in the city. In using Rossi's theory of monuments as elements that drive a city forward- some which are propelling while some pathological  , I would like to argue the point that the street within a city fabric are propelling elements that has the monumental nature of determining the character of an area and the architecture correlates to this phenomenon of street pattern. The functions within a building and the street life adjoining the building have a mutual and correlative relationship. The street life around a monument for example a church or a historic public building is determined by the architecture. The architecture determines the street character and vice-versa.
Rossi states that 'The quality of architecture- the quality of the human creation- is the meaning of the city.'  The quality of the architecture is determinant in the quality of the exterior as well. The quality of the street depends on the architecture adjoining it and its multitude of functions. The architecture- not necessarily built environments, open spaces like public squares and parks equally have the power to determine the flow of people. An arcade of columns along a street and a closed facade of an office building have different ways of communicating with the public. The Manhattan blocks though with its strong grid pattern of avenues and streets has unique and different qualities of urban areas. The pattern is constant but the quality is influenced by the urban architecture.
Koolhaas in his theory for Manhattan, states that 'Congestion itself is the essential condition for realizing each of these metaphors in the reality of the grid.'  The metaphoric planning for Manhattan as a very modernised Venice in Koolhaas terms were the foundation of a culture of Congestion'  I am turning to Koolhaas now to make my argument stronger on the role architecture plays in working with the congestion and the kinetics of the city. Relating to the skyscraper as a type, that in his terms adds on to the present congestion but at the same time has the ability to absorb the congestion. The architecture of Manhattan has the ability to direct and stabilise the congestion in an organised and systematic pattern. The skyscraper is the monument of Manhattan; they propel the city forward and frame the pattern and lifestyle of its citizens.
The Empire state building and the Rockefeller center best portray the culture of congestion that characterizes Manhattan. In describing the Rockefeller center, Koolhaas mentions Raymond Hood  the architect of the project as 'the center is the apotheosis of the vertical schism: Rockefeller center = Beaux-Arts + Dreamland + the electronic future + the Reconstructed Past + the European Future, "the maximum of congestion" 
The architecture of Manhattan could be best described from the Rockefeller center- an architecture of magnificent and absorption- a city within a city. Rossi states that 'Urban artifacts have their own life, their own destiny.'  The architecture of Manhattan as an urban artifact elucidates the concept of persistence, permanence and resilience in framing the city. In terms of the architecture of Manhattan determining the character of Manhattan, I would like to state Rossi's comment on cities as 'For the elements constituting the city- these urban artifacts which are by nature characteristic and characterizing and as much a product of human activity as a collective artifact- are among the most authentic human testimonies.'  The architecture of the city which is purely human creation in terms of Rossi determines the character and the nature of the city.