Mr Santos had supported Mr Uribe early on, founding a party to back Mr Uribe's campaign for president when the latter was still a relatively unknown candidate.

However, Mr Santos' approval ratings remained high and he resigned as defence minister in 2009 to be able to run for president in 2010.

They think there are another 8,500 civilians who make up the Farc's support network.

Inspired by the Cuban revolution in the 1950s, they demanded more rights and control over the land.

No, Colombia went through a 10-year civil war before the Farc were even founded.

The man who would later become the top leader of the Farc, Manuel "Sureshot" Marulanda, had fought in La Violencia.

Most of their fighters are from poor, rural communities and include both men and women of all ages.

Colombia is one of the main producers of cocaine and the rebels get a large part of their income from drug trafficking or levying "taxes" on those who do.

President Santos, a former defence minister, made it clear that his long fight against the Farc - as well as the secret channel he established two decades ago - gave him the gravitas to sit down with his enemy.

A 52-year war means a generation of pain and distrust.

The Farc, rooted in a Marxist-Leninist peasant revolt, must now move away from its vast network of criminal activities, including the lucrative cocaine trade, in exchange for entering the political process and becoming part of Colombian society.

But in what one UK pollster called “one of the biggest polling fails of all time,” the peace deal was narrowly rejected, with 50.2 percent voting against it. That means the peace agreement can’t be implemented — and is effectively dead.

he FARC is the Fuerzas Armadas Revolucionarias de Colombia (the Revolutionary Armed Forces of Colombia). It’s a Marxist rebel group that since 1964 has waged a bloody rebellion against the Colombian government — and it’s the longest-running armed insurgency in the Western Hemisphere.

Starting in 2000, the United States began providing the Colombian government with billions of dollars in mostly military aid to help interrupt the country’s massive drug trade and fight the FARC and other smaller rebel groups. The hope was that social and economic conditions in Colombia’s “historically marginalized” rural areas in which the armed groups thrive would also be improved.

Under the agreement, called Plan Colombia, the US pledged nearly $10 billion in assistance. As reported by the Washington Post’s Dana Priest, this was paired with “a CIA covert action program that has helped Colombian forces kill at least two dozen rebel leaders.”

The deal would also have allowed rebels to avoid jail time if they confessed to their crimes. Per the BBC, the agreement would have created “a special legal framework” intended “to try those who committed crimes during the armed conflict, including Farc fighters, government soldiers and members of right-wing paramilitary groups.”

The peace agreement as written cannot be implemented without an approval by referendum, so it will have to be renegotiated. President Santos has promised to “continue the search for peace until the last moment of my mandate, because that's the way to leave a better country to our children ... I won't give up,” he said.

Correspondents say President Santos has risked his political future on the success of the peace deal.

But after 50 years of war, many Colombians still aren't ready to forgive. As President Santos put it, the hard work of building peace now lies ahead.

President Santos said this historic moment was a message from Colombia to the world: no more war. "No more war," the crowd chanted in return.

However, only hours before the signing, the EU announced it would suspend the Farc from its list.

1964: Set up as armed wing of Communist Party2002: At its height, it had an army of 20,000 fighters controlling up to a third of the country. Senator Ingrid Betancourt kidnapped and held for six years along with 14 other hostages2008: The Farc suffers a series of defeats in its worst year2012: Start of peace talks in Havana2016: Definitive ceasefire

Spearheading the "no" vote in Colombia was former president and current senator Alvaro Uribe, whose father was killed by FARC rebels.

It has thrived as a stable democracy amid neighbors governed by leftist leaders.