A city in the ground

by Herman Rosenberg

Suspended pedestrian bridges, garages without columns, platforms with a parquet floor – The Souterrain in The Hague in not just simply a tunnel. It's evidence of Rem Koolhaas' dare-devilishness.

Architect Rob Hilz in the sunlight, which penetrates deeply into the tram tunnel. "It's not a tunnel, but a second city level." (photograph Frank Jansen)

The ground opens up at the Grote Markt. At least, that's what it looks like. The road surface inclines on the eastern side. A stylized crevice has been constructed in the ground. The glass eye forms the entrance to the Grote Markt underground tram station. It's the only place where the Souterrain comes up, and when it comes into view, it's like the hump of a whale in the waves.

Not just a hole with stairs, or a hut with a lift, but a playful and dramatic gesture. There are those kinds of 'plain' solutions elsewhere along the 1,250 metre trajectory of the tunnel, but here at the Grote Markt – an open spot in the old city – Rem Koolhaas and his staff at the Office for Metropolitan Architecture (OMA) grabbed their opportunity with both hands. The solution – lifting the tunnel slightly and dropping the surroundings a little – which is typical for the dare-devilishness that has made Koolhaas and OMA world famous.

Initially, architect Rob Hilz (40) was responsible for the Souterrain as the project architect at OMA. He later started up his own company LAB-DA and took the project with him, yet always remaining in contact with OMA. We enter the tunnel together through the entrance at the Grote Markt. In the meantime, Hilz gives an explanation about the fundamental idea from which the entire construction emanated. “This assignment was a genuine OMA project, because something completely novel had to be added to the city. We also wanted to approach such novelty in a new fashion. The municipality's brief was that the trams and cars had to be hidden away, but we rejected that idea. Traffic belongs to a city, it's part of urban life and of the urban economy. That's why we said: we don't like the idea of an 'under world' and an 'upper world'. We want a layered city; not a tunnel, but a building in the ground, a second city level. It's a backbone which joins transportation and shops to each other.”

We walk through the stretched out length of the parking garage. The place is high and light. Not a single column to be seen, so it's ideal for less-abled motorists. The concrete floors and the slightly curved roof are smooth. Yet the walls are rough and look unapproachable. Here, the concrete has been left unfinished, which gives it a sort of natural look. It looks as if the whole area has been chiselled out of a rocky foundation. Of course that is not the case, because what we are looking at here, are the solid diaphragm walls of cast concrete which carry the entire construction. The atmosphere here is determined by the shades of grey and the pale yellow light.

Hilz: “You probably think: how boring, but that's the whole point. Later on the cars will provide colour. If we'd designed a nice colour scheme, it would be out-dated in ten year's time.” Near Peek & Cloppenburg, the rows of parking bays are interrupted by a roundabout. It is currently a bare, black basin, but later it will be a bamboo forest. An underground park which structures the space and marks the roundabout. Above this is a large expanse of TL tubes, which imitates the daylight. An essential facility – otherwise the bamboo doesn't grow – with the quality of a light sculpture.

Glittering ribbons

Further along lies Spui Station, an area where everything comes together. While everything on the many levels makes a complex impression – cars driving above behind glass walls, deep down below lie the glittering ribbons of the railway tracks, and between both worlds, stairwells and bridges everywhere – it's quite clear to the user as to where he should be. That's because the construction is transparent. Those descending by escalator from Spui or from Grote Marktstraat, arrive at a pedestrian area where many other flows come together, yet the main aim – the tram track – is visible in the depths. The escalators leading to it are also visible. You can therefore see where you need to be.

Suddenly there's another OMA effect. Sunlight abruptly penetrates deep down into the ground. Both tram stations have also been built in such a way that a certain amount of daylight can enter. “We deliberately ensured that there's a high level of light” Hilz explains. “Sometimes there's even daylight. We don't want a tunnel atmosphere here. That is important for the social safety. Lots of light, so there are no dark corners or niches. Almost no columns. Lots of flowing lines, and what's very important, a mixture of functions. Take a look, here is the underground entrance to V & D. At a later stage, there'll be an entrance to the new C & A on the other side.”

Rob Hilz is proud of the construction. That's not only evident from what he says, but also from his body language. With his head held high, he strides across the platforms and the still unblemished floor of the garage, while he points out the high level of the finishings. The stairs and floors of the pedestrian areas are clad with blue Belgian limestone, the platforms are made of russet coloured wood, which makes them look like a ship's deck, and a lot of gleaming mat stainless steel has been applied. The materials contrast well with the rough concrete of the walls. Hilz is satisfied, but also feels a little tense. “I'm particularly interested in how it's going to function, but I also want to know what people think of it. They might think it's beautiful, or ugly, or even disgusting. As long as they have an opinion.”