What is the FARC?

Colombian voters on Sunday rejected a peace deal brokered between the government of President Juan Manuel Santos and the Revolutionary Armed Forces of Colombia, known by its Spanish acronym, the FARC.

The leftist guerrilla group has been fighting for 52 years, mostly in the remote jungles and rural regions of the South American country. Its leaders agreed to sit down for peace talks with Santos in 2011, starting a five-year process of intense negotiations held mostly in the Cuban capital of Havana.

Voters opposed the deal largely because it was too lenient on the FARC, a communist group designated as a foreign terrorist organization by the U.S. State Department. But what exactly is the FARC? Here's a closer look:

HOW DID IT START?

The FARC was formed in 1962 by a small group of armed farmers who were fleeing a 10-year civil war in Colombia known as La Violencia. The farmers were left out of a power-sharing agreement that ended the violence and installed a new federal government.

Inspired in part by Fidel Castro's rise to power in Cuba, the FARC argued that the new Colombian government was taking land from small farmers and granting huge swaths of farmland to wealthy landowners. The group adopted a Marxist-Leninist ideology, arguing for peasants they felt were being left behind in a country that favored the powerful.

HOW MANY MEMBERS DOES IT HAVE?

The group started with a few dozens peasant farmers in the 1960s but swelled into the thousands by the next decade. The group reached its peak throughout the 2000s, when it boasted nearly 20,000 members, according to Stanford University's Mapping Militant Organizations project.

The group has long been accused of filling its ranks by kidnapping children and indoctrinating them in the mountains and jungles of the country. Human Rights Watch estimates that 20% to 30% of all FARC combatants are under 18.

HOW DOES IT FUND ITSELF?

For decades after its founding, the FARC relied on kidnapping, extortion, illegal mining and "taxing" people and businesses in the areas it controlled. The big money came when Colombia became the main global source for cocaine in the 1980s. The FARC jumped into narco-trafficking, taking advantage of its control over remote territories of Colombia, where it was easy to conceal its activities.

The FARC exported so much cocaine that by 2000, it was responsible for 60% of all the cocaine that entered the U.S., according to a report from the General Accountability Office, a congressional watchdog agency.

It's impossible to know how much money the FARC derives from narco-trafficking since the group hides its money well, using offshore bank accounts, investments in Colombian businesses and properties and sometimes just burying it. But the government estimates it could have been up to $3.5 billion a year at its peak.

HOW VIOLENT IS THE GROUP?

The FARC has been responsible for horrific acts of violence throughout its five decades of existence.

Operating mostly in the rural corners of the country, FARC guerrillas have long terrorized citizens with murders, kidnappings and the constant threat of extortion. In 2002, the FARC kidnapped presidential candidate Íngrid Betancourt, holding her hostage until she was rescued, along with three U.S. military contractors, during a raid in 2008.

Members of the FARC assassinated a Colombian culture minister in 2001, hijacked a domestic flight carrying a senator in 2002 and is estimated to have kidnapped more than 25,000 people from 1970 to 2010, according to a report from the Council on Foreign Relations.