The victimization of civilians and combatants during internal conflicts causes large socioeconomic costs. Unfortunately, it is not clear whether peace negotiations can significantly reduce this burden. One key reason is the lingering presence of antipersonnel landmines, which are hidden underground and remain active for decades. Looking at the recent experience of Colombia, we quantify the number of lives saved by the reduction of landmine accidents and study the institutional conditions under which peace agreements can significantly reduce landmine victimization. Our findings highlight the importance of: reduced counterinsurgency campaigns, post-conflict information sharing, comprehensive humanitarian mine clearance and mine risk management campaigns.