Analysts sometimes speak of “two Gazas”, says David Ignatius in The Washington Post: “the visible one above ground and a vast network of tunnels below”. This honeycomb of underground passages, known as the Gaza “Metro”, will present a formidable challenge if Israel invades the strip. Hamas uses the tunnels to store rockets, artillery, ammunition and other war supplies – and to launch surprise attacks on Israel via passages that stretch under the border wall. Many of the 200-odd hostages taken by the terrorist group will also be hidden underground, along with their guards.
Bedouin smugglers built the first tunnels in the area after Israel and Egypt demarcated the border in 1981, says The Economist. Hamas took up the tactic two decades later, and by 2014, the tunnelling operation included 900 full-time staff across a network spanning 500km – “more than 10 times the length of Gaza itself”. Iran and North Korea are thought to have helped with the engineering; funding was raised by pitching the tunnelling projects as “commercial investment schemes, complete with contracts drafted by lawyers”. Locating and destroying the tunnels will be extremely difficult, to say nothing of fighting within them. The Israel Defence Forces have an elite unit called Samur (Hebrew for “weasel”) which specialises in the practice, and operates remote-controlled robots that can look for booby traps underground. But flushing out the Gaza Metro will be “the work of years”, not weeks or months.