What is at stake in the Colombian peace process?
The Colombian government and the country's largest left-wing rebel group, the Revolutionary Armed Forces of Colombia (Farc), are trying to end more than five decades of armed conflict.
The two sides started holding formal peace talks in November 2012 in the Cuban capital, Havana.
Since then, they have reached agreement on three key topics, but despite these achievements there is still widespread scepticism as to whether a permanent deal can be achieved.
The two sides say occasional setbacks are inevitable but stress they are committed to seeing the process through to the end.What is at stake?
According to a report by Colombia's National Centre for Historical Memory (in Spanish), more than 220,000 people have been killed in the armed conflict.
Eighty percent of them were civilians, the report says.
More than seven million people have registered with the government's Victim's Unit. The vast majority have been internally displaced by the violence, but many have also been kidnapped, threatened, injured by landmines or forcibly disappeared.
However, not all of the violence is caused by Farc insurgents.
The National Centre for Historical Memory found that more than half of the massacres in the past three decades had been carried out by right-wing paramilitaries, originally created to combat the Farc.
Criminal gangs vying for control of Colombia's lucrative cocaine production have also become an increasing threat.
The hope is that a permanent settlement with the Farc will allow the security forces to concentrate on combating that threat and protecting the civilian population rather than fighting a protracted battle with Farc rebels.Who is negotiating?
The government and the Farc rebels each have a high-profile team in Havana.
The government's team is led by former Vice-President Humberto de la Calle. Also part of the team are retired generals from the military and police forces, two institutions which had initially been very sceptical about the peace talks.
The guerrilla team is led by Ivan Marquez, a member of the Farc's secretariat, its highest body.
Leaders of key regional Farc command groups are also in Havana, including Pastor Alape and Pablo Catatumbo.
They include hardliners such as the rebel known as Romana, who was behind the rebels' strategy of mass kidnappings.
Analysts believe their presence in Havana shows the rebel group is united behind the peace process.
Cuba, the host country for the talks, and Norway, with its ample experience of participating in conflict resolution, are acting as guarantors.What has been achieved so far?
Agreement has been reached on three broad points, but under the terms of the negotiations, they will not be acted upon until a final peace deal has been signed.
In May 2013, after six months of talks, the two sides announced they had agreed on land reform, one of the most contentious issues on the agenda.
In their joint statement, they said that "this agreement will be the start of a radical transformation of rural Colombia".
The deal calls for the economic and social development of rural areas and the provision of land to poor farmers.
Another six months later, in November 2013, both sides agreed on the rebels' political participation should a peace deal be reached.
In May 2014, they forged a comprise on the illegal drugs trade, one of the main sources of funding for the Farc.
They said they would eliminate all illicit drug production in Colombia.What are the issues still outstanding?
There are still a number of thorny issues the two sides have to contend with.
They are: the rights of the victims of the conflict, the disarmament of the rebels and last but not least, how all the agreed points will be implemented.
Groups of victims have been travelling to Havana to put their views to the negotiators and a subcommittee has been created to look at the issue of disarmament.What is happening on the ground in Colombia?
When the negotiations first started, the Colombian government refused to enter into a ceasefire with the rebels, arguing that they had used earlier ceasefires to re-group and re-arm.
The two sides however, agreed that events in Colombia, such as the killing of rebels or soldiers, should not affect the talks in Havana.
However, when the Farc kidnapped an army general on 14 November 2014, President Juan Manuel Santos suspended the talks.
Farc negotiator Pastor Alape travelled back to Colombia and personally handed over the kidnapped general.
The negotiations resumed, but the event highlighted the fragile nature of the talks.
A month later, the Farc declared an indefinite cessation of hostilities - an unprecedented move for the rebels.
On 15 January 2015, President Santos said his government was for the first time prepared to begin talks on a bilateral ceasefire.
He said he had asked negotiators to start discussions "as soon as possible".Are Farc fighters likely to stick to a deal?
The presence of key Farc leaders at the talks seems to suggest widespread support for the talks among the rebel hierarchy.
According to the Colombian army, more and more low-ranking rebels are demobilising. In their debriefs they tell of the hardships they have endured during years of jungle warfare and their keenness to lead a normal family life.
But military experts fear some of the rebels, who often were recruited as children, know nothing but warfare and are at risk of joining criminal gangs if their units are dissolved.
Middle-ranking fighters who have been involved in the cocaine trade, one of the main sources of finance for the Farc, could also be of high value to drug gangs, whose promises of high profits are more attractive than reintegration into civilian society.What are the stumbling blocks?
There are powerful voices in Colombia questioning the peace process and criticising the government's "willingness to make concessions" to the rebels.
The most vocal critic is former president Alvaro Uribe, who argues the rebels are "getting away with murder", referring to an amnesty offer for rebels willing to demobilise.
In December 2014, thousands of people attended rallies led by Mr Uribe calling for "peace without impunity".
Mr Uribe said it was "better to protest in time than hand the country over to terrorism".
But there have also been mass demonstrations in favour of the peace process and President Santos has secured the backing of key European and regional leaders for the process and "post-conflict Colombia".