The Phalanx has no outside streets or open road-ways exposed to the elements. All the portions of the central edifice can be traversed by means of a wide gallery which runs along the second floor on the whole building. At each extremity of this spacious corridor there are elevated passages, supported by columns, and also attractive underground passages which connect all the parts of the Phalanx and the adjoining buildings.

Charles Fourier, “Street-Galleries” in Utopian City, 1822

Conversely, the world within the interior complexes is, at best, private/public space organised overwhelmingly around the imperatives of consumption. The move from outside to inside is a passage between worlds. ‘Step from the wind and cold on the street outside into the new urban realm. As the glass doors firmly close, the mental realm changes. We are inside, contained, separate, part of the system, a consumer, a pursuer, a cruiser.’

Trevor Boddy, ‘Underground and Overhead: Building the Analogous City’ in: Stephen Graham, Vertical.

Architektur als wichtigstes Zeugnis der latenten ‘Mythologie.’ Und die wichtigste Architektur des 19. Jahrhunderts ist die Passage. – Versuch, aus einem Traum zu erwachen als bestes Beispiel des dialektischen Umschlagens. Schwierigkeit dieser dialektischen Technik.

Walter Benjamin, Gesammelte Schriften, Band V.2, Das Passagen-Werk.

The inhabitants would blow up the catwalks: This is a picture of anti-reason itself, of error, of thoughtlessness. Madness. And all the solutions come to the same thing: separation of traffic according to speed. The pedestrian, from now on, will be confined to raised walks build up above the street, while traffic lanes remain at their present ground level. Madness.

Le Corbusier, Ville Radieuse, 1928.

Die Stadt war nun ausgeschachtet. Durch Tunnel
Führte ein besinnungsloser Verkehr.
Es gab keine Eingeweide mehr, Labyrinthe
Im Zwielicht, mit Gassen ins Unbewußte,
Straßen, die in die eigene Blutbahn führten.

Durs Grünbein, Zündkerzen.

Wider processes of social polarisation have often worked to exaggerate the social separation of inside and outside within the downtowns of various North American cities. […] the city’s skyway system ‘became something it was never intended to be: a fortress, a filter, a refuge.’ The city’s downtown street system –an increasingly residualised space for the poor, the mentally ill and the failed consumers externalised from the interior system– became a source of fear for those inside.

Stephen Graham, Vertical.

En 1820, on ouvrit … les passages Viollet et des deux Pavillons. Ces passages étaient une des nouveautés de l’époque. C’étaient des galeries couvertes, dues à l’initiative privée, où l’on installa des boutiques, que la mode fit prospérer. Le plus fameux fut le passage des Panoramas, dont la vogue dura de 1823 à 1831. Le dimanche, disait Musset, la cohue ‘Est aux Panoramas ou bien aux boulevards”. Ce fut également l’initiative privée qui créa, un peu au hasard, les cités, courtes rues ou impasses édifiées à frais communs par un syndicat de propriétaires.’ – Lucien Dubech, Pierre D’Espezel: Histoire de Paris, Paris 1926.

Walter Benjamin, Gesammelte Schriften, Band V.1, Das Passagen-Werk.

The residualised street can, in turn, all too easily become ‘no more than a traffic sewer or refuge collection zone’ (Trevor Boddy) –a place inhabited by the marginalised groups excluded by the security guards and cameras that police the corporate, interior zone. (…) the air-conditioned interior skywalk cities will also exaggerate the urban heat-island problems.

Stephen Graham, Vertical.

Impressed by the emerging modernist experiments in Europe, North American master planners in the 1960s also embraced the idea of the multilevel city as a radical means of renewing and decongesting decaying urban cores so they could accommodate mass automobile use and compete with the burgeoning malls in the suburbs.

Stephen Graham, Vertical.

Some of the largest interior cities have been built in cities with particularly extreme climates. Indeed, the 18-km system of skywalks in Minneapolis is so extensive that its various routes are coloured and named like subways line to minimise confusion.

… a motivation […] were the advantages to real estate developers or the ability to connect large systems of multilevel car parking garages directly to commercial or retail space.

Stephen Graham, Vertical.