The second phase of The Eden Project’s development refers to the ‘biomes’, a sequence of eight inter-linked geodesic transparent domes threading around 2.2 hectares of the site, encapsulating vast humid tropic and warm temperate regions. Grimshaw’s design of the biomes is an exercise in efficiency, both of space and of material. Structurally, each dome is a hex-tri-hex space frame reliant on two layers. The efficiency of the frame relies on the components of the geometric shapes: steel tubes and joints that are light, relatively small and easily transportable. The cladding panels are triple-layered pillows of high performance ETFE foil and environmentally efficient, with maximum surface area and minimum perimeter detailing. The biomes received 1.956 million visitors in their first year of opening. The project is now one of the top three charging attractions in the UK and the second most visited destination outside London.