The world’s largest indoor rainforest offers more than just wow factor

Discovered in 2006, the Tahina Palm from Madagascar is one of the rarest plants on Earth. This enormous-leaved palm naturally grows only in one tiny pocket of the Indian Ocean island, and estimates suggest fewer than 100 live in the wild.

Which is why it is something of a surprise to encounter a Tahina Palm inside a former clay quarry in Cornwall, England.

But this new addition, planted in 2024, is far from the only extraordinary thing about the Eden Project. To all intents and purposes, it’s a big botanic garden. But the scale, ambition and architectural ingenuity make Cornwall’s most eye-catching attraction something much greater than that.

In March 2026, the Eden Project celebrates its 25th birthday. When it opened, there was something wildly futuristic about it – largely due to the enormous, visually striking, bubble-like biomes.

This series of interlinked geodesic domes, constructed from steel tubes and hexagonal, pillow-like ethylene tetrafluoroethylene panels, were a revolutionary take on the humble greenhouse. With one biome devoted to Mediterranean-style climates – including California and south-western Australia – and the other to the tropics, the Eden Project could showcase a remarkable range of plant life.

What’s more, it can do so with extraordinary landscaping. The 1.56-hectare Rainforest Biome is shaped into multiple levels under the 55-metre-high roof. What has become known as the world’s largest indoor rainforest includes a long wobbly bridge walkway through the treetops, a traditional wooden house from Malaysia and a multi-tier cascading waterfall.

However, if the Eden Project was just a wow-factor way of showing off plants, there’s every chance it could have been a hugely expensive dud. Beyond the cool-looking domes, it has been driven and elevated by a very prominent sense of purpose.

The mission behind it is tempting to pigeonhole as green evangelism, but there’s a lot more to it than world-saving eco-stereotypes. There’s a strong emphasis on sustainability and ecologically sound practices, but there’s also a recognition that humans are a part of the systems rather than weapons sent to destroy them.

Indeed, the most compelling section of the rainforest biome is the one that focuses on how people have cultivated and used rainforest plants. The walk through takes in rubber trees that become tyres, the palms grown in vast swathes for palm oil, the Manila hemp that is turned into rope and the cloned Cavendish bananas that have taken over the world’s grocery stores.

There’s also a big, garishly painted sugar truck, which is the starting point for a thoroughly surprising dive into the global sugar industry. More than 1.9 billion tonnes of sugar were produced across 90 countries in 2022 – that’s more than 2½ times the amount of wheat in the same year.

With gentle preachy mode activated, visitors are introduced to panela – an unrefined sugar cane that retains the vitamins, minerals and proteins that processing usually strips out.

Environmentalism and education go hand in hand here. For me, what turns an enjoyable walk through a remarkably created rainforest into something special is that I am constantly learning new things. For example, 70 per cent of people in Madagascar make their living from vanilla – which has to be pollinated by hand. And the seeds of the castor oil plant are used to make the deadly poison ricin. And Jamaica’s national fruit, the ackee, is banned in the US because it is highly toxic when unripe.

The architecture and the setting bring you to the Eden Project, but it’s the constant stream of “ooh, I didn’t know that” nuggets that keeps you there.

It also turns out that the most endearing thing inside somewhere so spectacularly large is something charmingly small. Strutting between the big banana leaves are colourful roul-roul partridges, native to South-east Asia. They are the police in these parts, used instead of man-made chemicals to keep the insect population in check.

The roul-rouls are adorable to look at, especially when a mother shuffles past with her chick, but they also show that the Eden Project isn’t just about plants – it’s about ecosystems. Thinking much bigger didn’t stop with the design of the biomes.

THE DETAILS

Visit
The Eden Project is in Bodelva, near St Austell in Cornwall, south-west England. Advance-booked tickets cost £38 ($75). Expect a 4¼-hour drive from London Heathrow Airport. See edenproject.com

Stay
The three-star Premier Inn in nearby St Austell offers doubles from £55 ($114) a night, room only. See premierinn.com

More
Visitcornwall.com, visitbritain.com

The writer travelled as a guest of Visit Britain and Visit Cornwall.