Story highlights Colombian rebel group signs deal to end over half a century of armed conflict

Deal still needs to be ratified by electorate in an October referendum

(CNN) A conflict that lasted over five decades. An estimated 220,000 people killed. Five million displaced.

These staggering figures are now consigned to history as the Colombian government buries the hatchet with its longtime nemesis, the Marxist Revolutionary Armed Forces of Colombia rebel group, better known by its Spanish acronym, FARC.

The pen used to sign the treaty is made from a bullet used in combat.

In a symbolic gesture, the pens used to sign the historic peace deal, years in the making, have been made from recycled bullets once used in the conflict. An inscription on the side of the pens reads: "Bullets wrote our past. Education, our future."

The two sides, joined by leaders from the United States, Mexico, El Salvador, Uruguay, Cuba and the United Nations, came together on Monday in the coastal colonial city of Cartagena to sign the accord.

"Today, Colombians are bidding farewell to decades of flames, and sending up a bright flare of hope that illuminates the entire world," UN Secretary-General Ban Ki-moon said at the signing ceremony.