Colombia is among the most heavily mined nations in the world. The mines are deployed by illegal armed groups waging an internal armed conflict against the Colombian state going back many decades. Many of the mines are of Eastern European origin or improvised explosive devices, and poor documentation by the offending groups on where land mines are deployed has created a situation throughout Colombian territory where innocent civilians and livestock wander into unmarked or forgotten minefields and detonate the devices. This article examines the problem of landmines in Colombia and the challenges of holding illegal armed groups responsible for the deployment of deadly “silent sentinels.”