The United Nations said it has concluded the disarmament process for individual arms as part of a peace deal between Colombia's leftist rebels and the government.
At a ceremony in eastern Colombia UN observers closed the final container holding some of the 7,132 assault weapons collected at rebel camps nationwide in recent weeks.
President Juan Manuel Santos and top leaders of the Revolutionary Armed Forces of Colombia (FARC) were present for the act.
"In a world convulsed by old and new forms of violence, by conflicts whose protagonists appear irreconcilable ... a successful process constructing peace in Colombia is also reason for hope and a powerful example for the international community," said Jean Arnault, head of the UN peace mission in Colombia.
The historic feat places the nation one step closer to turning a page on Latin America's longest-running conflict that has left at least 250,000 people dead, another 60,000 disappeared and millions displaced.
"This is the most important decision a guerrilla can make, to give up weapons," said Aldo Civico, a professor at Rutgers University and expert in Colombia's conflict.
FARC rebels reached an agreement with Colombia's government last year to give up their weapons and transition into a political party, but implementing that accord has been slow.
A national referendum on the agreement failed by a popular vote, congress has struggled to pass laws implementing the revised accords and opposition politicians are threatening to overturn key aspects of the deal if they win the presidential election next year.
Controversy has also dogged the weapons hand-off, with conservative former president Alvaro Uribe leading a chorus of opponents questioning whether the FARC has turned over its entire arsenal.
"In the administrations I oversaw, there was talk of many more weapons," the still popular Mr Uribe said in Madrid last week.
But frustration is also growing inside the rebel ranks and guerrilla-dominated communities.
Today a smooth paved road connects Mesetas with Bogota, but the community suffers from the same neglect and inequities that gave rise to the conflict.
Like many other places torn by war, residents of the small town voted overwhelmingly for the peace agreement last year, though many still harbour doubts as to whether the guerrillas will follow through on their pledge to completely disarm and abandon their involvement in Colombia's flourishing criminal economy.
At the nearby Mariana Paez camp, the concrete housing units with running water, kitchens and electricity that the government promised are still a distant vision for rebels living under plastic covers in what is one of the nation's most underdeveloped demobilisation zones.
The settlement, named after a prominent female ideologue killed in combat in 2009, is located high up on lush green mountains that have long been a FARC stronghold and was witness to some of the conflict's worst atrocities.
Peace has tried to root itself here at least once before.
In the nearby town of El Uribe, the rebels signed a ceasefire agreement with the government in 1984.
The accord eventually failed, paving the way for a decade-long bloodletting in which as many as 3,000 members of a FARC-aligned political party were gunned down.
Lingering memories of the extermination campaign weigh heavily on the guerrillas, many of whom expressed their fears about returning to civilian life without weapons.
The more recent rash of killings of dozens of social leaders is also heightening concerns.
Some guerrillas, who now wear jeans instead of fatigues, wonder if it is safe for them to leave.
Ilich Ceron, a member of the FARC's communications team, said the rebels on Tuesday want to disprove any rumours about hidden stockpiles of weapons never declared or turned over to the UN.
"We are giving the country our ethical and political commitment that we're giving up weapons," Ceron said as crews built the stage where the disarmament ceremony would take place amid pouring rain.
But do not expect a photo op of rebels surrendering their weapons.
During years of peace negotiations in Cuba, Ceron said one thing the guerrillas made clear is that they never wanted to be seen as a vanquished army.
Experts at Notre Dame University's Kroc Institute for International Peace Studies said the one gun per fighter ratio seen in Colombia could be one of the highest in the world, far greater than the levels of disarmament seen in recent guerrilla conflicts from Guatemala to Nepal.
Mr Civico said doubt over the exact number of weapons turned in ultimately does not matter in measuring disarmament's success.
"There's always a question mark," he said.
"What's more important is we are witnessing step after step the willingness of the FARC to really demobilise and reintegrate and that should be reinforced by the state and government in fulfilling the promises and agreements signed."