The Eden Project is one of The Millennium Commission Landmark buildings. The Millennium Commission wanted both to look at and record the past. Also to look towards the future. And that's really why Eden is such an appropriate way of marking this important anniversary. The planet offers a scarce resource and is something we have to work with and live with. And Eden really celebrates this learning to live with the planet. The planet of course is divided into different environments and one of the initial ideas that we pursued was to create a complete world environment. And rather than just a collection of plants, we wanted to completely recreate the humid tropics which many of us know as the 'rain forest'. And of course there is a great tradition in this country, for the last several hundred years, of exploring the planet, finding new plants and bringing them back to where it's quite a cold, temperate environment, and this has generated a new architectural form which is often utilised in emerging technologies, and in particular wrought iron and mass production techniques. So we have great glass-housing designers such as Paxton, and eventually the Crystal Palace. But for me, one of the fascinating designers was Loudon. And here we have a building, one of the few remaining buildings - it's not so far from Eden - which really utilises wrought iron technology. And what you can see is a very light delicate structure. It has almost no structural support other than the envelope itself, so a real celebration of that emerging technology. We were first approached on Eden in 1995. We had just completed the new terminal at Waterloo, and Tim Smit and Jonathan Ball, the two founders of Eden, had seen the project and thought that would make the sort of architecture they were after, some large-span steel and glass structure which could house their ideas of a very large conservatory to allow plants to grow to their full maturity.

The site however is in a disused pit in the middle of Cornwall. Cornwall has an industry of removing clay; and clay, like China clay, you often see in all sorts of products coming from very white paper to pharmaceutical products even, very fine white powder. And it's removed by basically using high-pressure water. In other words, it's quite soft, and although the pit looks as if it's a large hole in the ground made of rocks, in fact large sections of it are very unstable. The other important thing for architects is working in a sensitive way with the environment. And it's something we've been exploring in the office for some time. In fact, we are one of the first large practices to be given what's called ISO 14001 which is an international standard for environmental awareness. And it follows a system we call EMS which stands for Environmental Management System. And what we do is we audit all of our designs at certain times throughout the design process. We look at the impact, we look at the site that we're using. Here of course we're regenerating an old quarry. We‘re actually bringing lost ground back into use. But also we look at the source of materials that we use for our structure, we look at the embodied energy in the materials, we look at potential damage in manufacturing, we look at whether these materials can be recycled and re-used. So you're doing things really in a very conscious way, making decisions that have been carefully considered. From day one we decided first of all to use the pit as part of the architecture, that the buildings would effectively use the shape, the topography, to create interesting exciting volumes, and the buildings would lean against the edges of the quarry. However, one of the key problems we faced was the soft ground and how that would be stabilised, and we worked very closely with the engineers Anthony Hunt Associates, not only on developing the structural system but also on how the ground could be stabilised and how we would deal with the very complicated foundation system in this forever changing level. As well as ground stability, the other key problem we had at Eden was the amount of water. Now in the long term this is very advantageous because of course we need water to water our garden. But we're actually below the water table and so we have to pump water round the clock. If we didn't pump water slowly, we would turn into a lake. So the water is moved. All the water that falls on the buildings is collected and that's relatively clean water and it's collected and held in a large pond we can then use to irrigate all of the garden, both inside and outside. So to develop our architectural ideas and indeed engineering solutions, we first of all had to understand the site, not only the actual conditions of the site - i.e. what was soft, what was hard - but obviously its three-dimensional form And this was done by taking a whole series of photographs and measurements that allowed us to build a completely three-dimensional topographical form of the site.