More on the FARC and drug money in specific:
Until the 1980s the growth of the FARC was slow, restricted mainly to the outer reaches of the country where hardy peasants had carved land from the jungle and where the state has neglected to follow them.
But then the FARC discovered drugs - not consuming them, which is prohibited in the rebel ranks, but taxing them.
Now they tax every stage of the drug business, from the chemicals needed to process the hardy coca bush into cocaine and the opium poppy into heroin, right up to charging for the processed drugs to be flown from illegal airstrips they control.
And they make at least $300m from the drug trade every year, added to which is their income from kidnapping and extortion, making them probably the richest insurgent group in the world.
Source: :Colombia's most powerful rebels
(Can anyone tell what I have been working on lately?)