Eden Project. Panoramic view of a gardener watering young plants in a nursery at the Eden Project in Cornwall, England. The Eden Project is a horticultural garden centred on two large greenhouses (biomes). These plants are being reared before being planted in the humid tropics biome, which houses rainforest plants. This biome is 55 metres tall and 240 metres long. The Eden Project shows the diversity of plant life across the world, and how humans interact with it. It was completed in spring 2001.