Hamas tunnels under Gaza will be a key battlefield for Israel

STUDENTS OF urban warfare divide the battlefield into four planes. One is the sky above cities, increasingly thick with drones. Next are the buildings that extend upwards, offering vantage points and hiding places. A third is the streetscape: the lattice of roads, alleys and paths that form a city’s peacetime arteries. It is the fourth—the tunnels lying beneath—that will present the greatest challenge to the Israel Defence Forces (IDF) when they begin their invasion of the Gaza Strip in the coming days.