Colombian President Juan Manuel Santos and Marxist rebel leader Timochenko will use a pen made from a bullet on Monday to sign an agreement ending a half-century war that killed a quarter of a million people and made their country a byword for violence.
After four years of talks in Havana, Cuba, Santos, 65, and Timochenko - the nom de guerre for 57-year-old revolutionary Rodrigo Londono - will shake hands on Colombian soil for the first time.
Some 2,500 foreign and local dignitaries were due to attend the ceremony scheduled for 5 pm local time (1800 EDT/2200 GMT) in the walled, colonial city of Cartagena.
The agreement to end Latin America's longest-running war will turn the FARC guerrillas into a political party fighting at the ballot box instead of the battlefield they have occupied since 1964.