Under all of the destruction in Gaza — buildings toppled, cars crushed, smoke and fire — there are unseen miles of tunnels. Some are reportedly more than 100 feet deep. They've been built and rebuilt over the years at a cost of tens of millions of dollars. The system is sometimes referred to as the Gaza Metro.
"They were constructed since even before 2007 when Hamas took control of Gaza, and they used to run from the Egyptian border into Gaza. They were initially smuggling routes to get weapons and other material to the terrorists in Gaza," said Gerard Filitti, senior counsel at The Lawfare Project.
Video made by The Associated Press shows the inside of a tunnel in the Gaza Strip discovered by the Israeli military in 2013.
It's made of concrete and stone. The first were built in the early 1980s to smuggle in and move around goods like food and medicine after an Israeli blockade.
"It would say it's, it's important not just for Hamas, but even for the population in some ways to survive if they're not getting adequately what they need because, you know, Israel and Egypt are in control of the movement of people and even goods that come in and out of there," said Eric Lob, professor of politics at Florida International University.
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Video posted by the Israeli military in July of 2022 shows what it says are weapons hidden inside the tunnels.
Over the years, they have expanded as a way for the terrorist organization Hamas to maintain a stockpile of weapons including rockets hidden from the view of spy satellites.
Military experts say while valuable for transportation, storage and hiding the tunnels also have a psychological use. It's an unseen, unpredictable angle designed to keep enemies wondering when and where they’ll be ambushed.
"This poses a particular risk for the IDF going into those tunnels physically to secure them, especially when you don't know the layout, you don't know what to expect down there," said Filitti.
Experts say the underground spaces could be a challenge in a ground war in Gaza.
"We can't send in U.S. Special Forces or Israeli Special Forces to secure the release of our prisoners if we don't know where they are, if they're in miles worth of tunnel underground," said Filitti.
Video from an Israeli weapons maker shows how so-called bunker buster missiles are built to burrow into the ground before exploding.
The Israeli military says tunnels used by Hamas were among the hundreds of targets it hit this week. The Israel Defense Forces released a map showing tunnels under Gaza city and other locations, at least one of which they said was being used to smuggle weapons.
