Operation Protective Edge has brought unprecedented attention to tunnel warfare, and we can expect tunnels to remain center stage as the conflict winds down and inquiries – legal and otherwise – related to the conflict are launched. Though tunnels were used by the British Army during World War I, the Vietcong in Vietnam, Al Qaeda in Afghanistan, and even the rebels during the current conflict in Syria, tunnels have not been seen as a key strategic threat in decades – until they formed the Israeli government’s main justification for Operation Protective Edge this July.