Deep blue.

North Greenwich is the station for the vaunted Millennium Dome, and is the only underground one shown in detail in this issue. An awesome blue cave has been created as a spectacular celebration of arrival and departure.

Formerly a bleak, remote and polluted tract of land, North Greenwich peninsula is being energetically transformed as the site of Rogers' ubiquitous Dome (AR February 1998) and Millennium Village, a mixed development masterplanned by Ralph Erskine. Beyond the millennial machinations, the Jubilee Line Extension (JLE) will connect the peninsula with central and east London, bringing radical and greatly needed improvements to the area's transport infrastructure. (Above ground, the new station is linked to an elegant, airy bus terminus, designed by Foster and Partners.) But the presence of the Dome and its predicted torrent of visitors means that North Greenwich is more than simply a local station in an obscure part of London; instead it forms a public gateway to the revitalized peninsula.

The only station on the JLE to be built on a completely clear site, North Greenwich is a subterranean set piece theatrically orchestrated by Alsop Lyall & Stormer. The initial design was based on the notion of an open station that allowed passengers to enter the ticket hall along a central landscaped walkway, suspended on reinforced cross beams spanning the station void. A cut and cover solution was finally adopted, so that the entire station is now underground, but the choreography of changing levels, soaring voids and exposed vertical circulation give the scheme a dizzying, Piranesian quality underpinned by some muscular civil engineering. The station is contained within a cofferdam 400m long, 30m wide and 25m deep. (The excavated hole was large enough to accommodate Canary Wharf Tower laid on its side.) The station structure itself is a large concrete box, 380m long, 22m wide and 22m high. As there are no intermediate floors within the central public area of the box to carry lateral loads, two rows of raking, aerofoil-shaped concrete columns 13m high act like trusses, supporting the roof slab above. Hanging concourses and banks of escalators and stairs reveal the imposing presence of the structure.

The ticket office is located on an upper level toward the west end of the station. From here, passengers move to a concourse suspended from the concrete roof structure. Voids on either side of the concourse enclosed by glass panels offer views of the platforms below, inducing a sense of openness and transparency rarely experienced in London's cramped and dingy tube network.

The heroic scale and simple elegance of the civil engineering structure are reinforced by vigorous use of colour. Walls, floors and ceilings are coloured a seamless, intense blue. Cobalt mosaic tiles and glass combine to give a sumptuous, otherworldly dimension to the cavernous space. Suspended in the ultramarine void, a network of gleaming stainless-steel ducts and escalators adds to the visual richness and complexity. Cobalt blue has become something of an Alsop signature - the scaly ultramarine tiles and organic structure of the government headquarters in Marseilles (the 'Big Blue', AR October 1994) have a similarly surprising yet seductive resonance. At North Greenwich, the painterly intensity of the gorgeous blue void elevates the mundane, people-processing business of shuffling to and from underground platforms into a mesmerizing journey through a magical interior realm.

Architect Alsop & Stormer, London, previously Alsop Lyall & Stormer

Design team W. Alsop, C. Egret, P. Angrave, J. Smith

Civil and structural engineer Benaim Works

Photographs Dennis Gilbert/VIEW