Most of Colombia's 3,000-odd kidnappings every year are carried out by the FARC rebel group, who use the ransoms to fund their long-running war on the state.
The group's roots can be found in the Liberal guerrilla bands of La Violencia, a civil war between the Liberal and Conservative parties that raged from 1948 until 1958, which became disillusioned with the leadership of the Liberal Party and turned to
FARC denies responsibility for the deadly Bogota club bombing
One such guerrilla band was led by Manuel "Sureshot" Marulanda (his real name is Pedro Antonio Marin), who in 1966 baptised his group the Revolutionary Armed Forces of Colombia (FARC).
Manuel Marulanda, now more than 70, still heads the FARC.
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.
The FARC did briefly flirt with a political route to power, establishing a political party, the Patriotic Union (UP), in the late 1980s.
But the UP was decimated by right-wing death squads, sponsored by drug traffickers and with links to government security forces.
Some 3,000 UP members were murdered, including the UP's 1990 presidential candidate,
Bernardo Jaramillo Ossa.
The political route was therefore effectively
closed to the FARC and they focused on the military route to power, which they are still following today.
In 1998, the rebels were granted a 42,000 sq kilometre safe haven in 1998 by then President Andres Pastrana - their condition for sitting down at the peace table.
But the FARC talked peace with the government while making war, bringing violence and
kidnapping to record levels.
They used their safe haven to import
arms, export drugs, recruit minors and build up their military machine.
The territory was revoked last year by a new government under President Alvaro Uribe, who cancelled the peace talks after FARC rebels hijacked an airliner, forced it to land on a rural road and kidnapped a Colombian senator who was aboard.
President Uribe and the Colombian army have this year launched a fresh offensive against the rebels - backed by $3bn of US military aid.
While the tide is believed to be turning against the FARC, the rebels still believe they can take power with violence.
In September, eight people were killed - including a two-year-old child - after a bomb strapped to a horse has exploded in a market. The FARC was blamed.
The group was also accused of a deadly bombing at a Bogota social club earlier this year, which killed 33 people, although it denies the allegation.