The Serpentine Gallery have described their commissioning of the LA-based Aitken as amongst their most ambitious projects. Certainly the building itself has been used in a radical new way to create an all-encompassing installation, but Aitken's work is essentially more conservative than the "new approach" might imply.

The first really big difference this visitor noticed is that the usual access is denied -- instead a cheery-faced Serpentine employee points the way to a mysterious door next to the ladies' toilets. The space normally occupied by the entryway is blocked over with a collection of lines in shades of blue, together with the title of the work, the enigmatic new ocean. The installation proper begins as one descends the stair behind the mysterious door, and sounds of water and cracking ice greet the viewer. The descent itself is fascinating; the bowels of the gallery are not normally open to the public and there is a certain degree of "truant excitement" born form the bare breezeblock walls and insulated pipes. Rounding a corner the viewer meets a huge triptych of video screens. In the basement of the gallery, with the heating ducts above you, you are assaulted by light and the sounds of water and ice. The triptych is used very effectively, with mirroring effects and co-ordinated motion across the screens. Clever inversion of the images, together with movement and scale, create an immersive environment: womb-like images of ice caves add to the effect. The images of melting ice give a first explanation of the title of the work, new ocean.

Climbing a set of fresh-built stairs leads to the main portion of the work, and into the regular gallery space. The entire gallery has been darkened and shaded in blue, creating the impression that the immersion of the triptych has come to pass. The first of the parts that form the whole the visitor sees is a light-box photograph of a man in an ice cave. Although he is in silhouette, the human form is triumphant and a surprise addition after the film below. The rest of the installation includes a fair amount of people, barging into the new ocean in much the same way the observer does. The Serpentine has been set up symmetrically, with two routes to the "heart" of the piece. Each route involves passing through a room showing a video projection, a circle around two feet across. The two videos are different: one shows drops of water (a vertical, natural progression); the other shows motions through an industrial landscape towards an endless supply of white discs. As each disc fills the screen, the next landscape appears, the inevitable white disc in shot. The contrast of this horizontal, artificial progression is clear and intelligent, but I for one felt like I was watching a Pink Floyd video.

The next "paired" rooms use video projection in another intelligent way, the film projected onto a set of screens arranged as a hanging cross, as if some titanic Risk piece had been hung from the ceiling. The effect is, once again, to immerse to viewer in these very human films, featuring male and female figures in motion. The measured progress of the "dot" rooms contrasts sharply with human movement- even at its most graceful the body cannot achieve true fluidity. These "cross" rooms then lead to the final sanctum, a room made circular by screens. Nine projectors, one backlighting a circular screen above the viewer, fill the room with images of water seen from above and below. The room is the triumph of immersion -- one point of the film has the viewer thrust below the waters and looking up at a diver on the ceiling. The human and watery aspects of the work are combined in this room, with the viewer effectively becoming the man in his ice cave, surrounded upon all sides by water. Of particular beauty is Aitken's film of waterfalls, reflected in adjacent screens to form organic, flower-like forms. This room is the high altar of the work, and indeed the dark, mysterious installation has the feel of a temple or sacred site. In this Stonehenge of water the viewer is right inside the new ocean.

Doug Aitken's new ocean is an unusual and large work, pulling the viewer into itself. Despite the gallery's claims of radical departure from the norm, the work creates a sense of calm- it seems had to comprehend anything "radical" within the blue walls of Aitken's womb-like world. The sheer amount of water gives the piece a very "female" feel too, comforting as it enfolds the viewer. The whole piece feels a little conservative: as a set of "modernised" seascapes, it has not the energy of the storms portrayed by, say, Turner. It encourages a slow exploration, only fully gripping the viewer in the final, round room. It is a very peaceful work, despite the occasionally loud noise, and the sense of detachment from the world is strong. I thoroughly recommend a look around, especially after that over-long board meeting or horrendous Tube trip.