I'M in a steamy tropical environment in a most unlikely place - Cornwall in south-west England.
In fact, I'm in a biodome, an enormous bubble of controlled air temperature in which a huge range of tropical plants has been cultivated.
Only metres away, outside the dome, the air temperature on this English winter's day is around freezing.
This is the Eden Project, a creation of a global garden on 14ha - the area of 30 football pitches - of a 50-metre deep crater that was for 160 years a china clay pit near the coastal Cornish town of St Austell.
It's a living laboratory which, since opening in 2001, has attracted more than 13 million visitors and is one of the most popular tourists attractions in the south of England.
As well as creating stunning gardens, much of the Eden Project's energy goes into running environmental projects around the world and doing valuable research into conservation.
The brainchild of entrepreneur Tim Smit, it celebrates the planet's dependence on plants for food, fuel, medicines and materials.
While Smit was restoring nearby Lost Garden of Heligan he realised that plants could be made far more interesting by weaving human stories around them - tales of adventure, emotion and derring-do.
He reasoned that there were big stories to be told about plants that changed the world.
He assembled a team to put the largest greenhouses in the world into this huge hole.
The result is two vast domes - Eden calls them biomes - that look like translucent golf balls sliced in half.
The covered biomes are constructed from tubular steel clad with plastic panels with no internal supports. The soil, 83,000 tonnes of it, was made from 'waste' materials.
While there's plenty for adults to enjoy about the Eden Project, clearly the aim is to educate and entertain children. It does that splendidly.
The project, which has a staff of 500 plus 300 volunteers, is great for kids.
There are imaginative children's play areas, impromptu storytelling, banks of microscopes where we gaze at living insects and plant matter, and workshops for all ages.
From the entrance, we view the breathtaking landscape of the Eden Project, with its many seasonal colours, sculptures and world-famous architecture.
Once inside the project's grounds, we walk a meandering path through an outdoor, uncovered biome which represents the temperate regions of the world with planted landscapes.
Here are orderly vegetable gardens and plants such as tea, lavender (a sign encourages us to sniff and feel), hops, hemp and sunflowers.
Beyond are sculptures that include a giant bee and a towering monster created from old electrical appliances. (Reminding us that we live in a throwaway society.)
Ahead are the two enclosed biomes.
They house landscapes from rainforest to Mediterranean regions - plants from every corner of the world. (We could have boarded a road train which takes visitors in comfort to the centre of the complex to begin their walk through.)
The climate in these covered biomes is controlled automatically. Main source of the heating is the sun working like a typical 'hothouse', summer and winter.
In these biomes we travel the world, trekking through the world's largest captive rainforest, walking wild landscapes, meandering through the Mediterranean, tracing plants and their origins, and exploring the relationship between plants and humans.
As we walk the winding paths we spot birds and lizards, imported to control pests. We can't see them but there are also friendly bugs that eat unfriendly bugs.
The Eden Project's 'Green Team' has planted millions of plants of around 5000 types - half a million bulbs every autumn and about 60,000 new plants every year.
"We are not a botanic garden," Smit said.
"We are about putting plants in their context. We want people to enjoy the atmosphere and sense of place. "
I'll have to come back on another - warmer - day to enjoy an exhilarating 660m flight on the Eden Project's new SkyWire, the longest zip wire in England, from which you can get a bird's eye view of enormous biomes as you soar over them.
The writer travelled at his own expense.
IF YOU GO
The nearest major town is St.Austell which is on the main railway line from London's Paddington station.
Buses connect to the Eden Project.
You can also get to Eden by walking, biking or car.
Walkers and cyclists enjoy a discount off the adult entry charge, and children under 15 accompanied by an adult come free.
If coming by car, Eden is well signposted from both the A30 from Exeter and the A391/390 from Plymouth.
Visitors from outside the county can take the M5 southbound, to Exeter, where the motorway splits into the A30.
Take the A30 and continue until you reach the Innis Downs junction (A 391) from which Eden is signposted.
There is ample parking at Eden and a park-and-ride service operates from the outer car parks.