Eden Project. Visitors inside the warm temperate biome at the Eden Project in Cornwall, England. This is a horticultural garden centred on two large greenhouses (biomes). The warm temperate biome houses plants from South Africa, the Mediterranean and California, USA. Together with the larger humid tropics biome, it forms the largest greenhouse in the world. The greenhouses are geodesic domes with windows of ethyltetra- fluoroethylene (ETFE) plastic. The Eden Project shows the diversity of plant life across the world, and how humans interact with it. Eden was completed in spring 2001.