I find the photo above worth a thousand words. James Rogers of Fox News reports:
. . . The scale and sophistication of the Hamas tunnels present a massive challenge to the IDF, which launched Operation Protective Edge on July 8 in response to an escalation in rocket attacks by Hamas. The ground phase began on July 17.
The tunnel network has been likened to a subway system. Often built with concrete blocks, the tunnels, which are used to transport Hamas fighters, for smuggling and for storing weapons, extend more than 60 feet below ground, according to news reports. A declassified aerial image provided to FoxNews.com by the IDF shows a concealed entrance to a tunnel located between a mosque and a school in a Gaza neighborhood. [my bolding]
As Israel continues its destruction of the tunnels, there has been considerable speculation in the Israeli media about what technologies it may be using to locate them, and about what improved detection systems may be on the horizon. . . .
Regardless of exactly how they’re locating the tunnels, the Israeli military is claiming success.
“Since the beginning of the ground phase of Operation Protective Edge, the IDF has uncovered over 31 terror tunnels as part of a vast and complex tunnel network planned by Hamas over the years,” the IDF spokeswoman said. “It is evident that Gaza is constructed upon a fully developed underground terror city which the IDF is at the peak of its unveiling and decommissioning.”