In a damp tropical night the plane from Miami judders through the clouds on its approach to Medellin airport.
Suddenly strange translucent patches come into view. Dozens of them in varying shapes and sizes dotted around the hilly landscape like giant stranded jelly fish, illuminated from inside, pulsating and sinister.
It turns out these are greenhouses. Medellin clings to the hills at 1,700 metres and at night the temperature drops by 10 degrees.
So the precious plants are kept reassuringly warm with artificial sunlight under plastic tarpaulins and close to the airport to allow for speedy delivery abroad.
The nurtured content is after all one of Colombia's most lucrative exports, sold for astonishing profits all over the world.
'A humble weed'
I'm talking about orchids. Yes, orchids! Colombia grows 450 different species of these delicate, exotic flowers. Seventy percent of the world's orchids come from here.
But the orchid is, of course, not the plant for which Colombia is best known. Orchids are not turned into powder and sniffed by millions of addicts in Europe and the US.
Orchids have not fuelled a guerrilla war, displacing two million Colombians and turning them into refugees in their own country. Orchids have not created a culture of violence.
No, that distinction belongs to an altogether less decorative plant - the coca leaf.
A humble weed, once grown by the Mayas and Aztecs to brew tea and numb the nausea of altitude sickness, today the alkaline distilled from it satisfies the most prevalent drug habit in the world. Unless you want to count alcohol of course.
An estimated nine million people sniff, snort or blow cocaine in Europe alone. Each day 5,000 more people worldwide will try the drug. Once a Yuppie accessory, "coke" has become a lot cheaper and a lot more common.
We were taken on a helicopter tour of Colombia's newest coca fields in the Macarena National Forest by Daniel Castiblanco, a police general who is waging a lost war against the plant on behalf of his government.
Sporting wraparound reflector specs and with two cell phones almost permanently clamped to his large ears the general clearly enjoyed giving us our tour.
When we wanted to fly lower to take a better look at the fields he did an impression of firing a gun and smiled.
I was sitting next to the gunner who had his gloved hand on the trigger of a 3,000-rounds-a-minute machine gun, made in Austria, searching for potential foes. I was trying to decide whether to feel reassured or terrified.
Sitting on the edge of a rickety Vietnam era US helicopter without doors you can see small patches of coca fields all the way to the horizon - hundreds of them, some no bigger than a hectare, but all of them planted very efficiently, delivering several crops a year.
Next to the larger fields is a small hut or house. "We call them the kitchens!" the general bellowed over the noise of the rotor blades. "It's where the first stage of production takes place."
The leaves are shredded, dried and then cooked with chemicals that distil the alkaline that makes the drug.
The farmers make a lot more from coca than pineapples or bananas but their profits are miniscule compared to those earned along the winding smuggler's route that finally ends in Europe or the US.
The government here is prevented by law from using pesticide to eradicate the plants in this part of the jungle, so the only way to get rid of them is to tear them out by the root one by one.
The problem is that the eradicators are easy targets for the guerrillas. Last month the government had 900. Now they're down to 150 in this area.
Many have simply fled and the few that are left need to be guarded by hundreds of officers to provide security. In our two hour flight we must have seen more than 200 coca fields. There was only one in which people were tearing up the plants.
Despite billions of dollars in aid, the US and Colombia are losing the battle to cut the supply. Perhaps it's time to look again at the demand and ponder options like legalisation.
But that, you might say, is a far trickier story because it's about our addiction and not about their economies.