Just south of where CBS News correspondent Richard Roth reported from, Gaza's 25-mile long Mediterranean Sea coast is sealed off by an Israeli naval blockade.
Gunboats off shore command the sea, and block access to Gaza's port.
All along their land border, high-tech fences and constant patrols separate Israel and Gaza.
And, helped by $23 million of American aid last year, Egypt too has beefed up security along its short frontier.
So Gazans get over their border by going under it, through a network of tunnels that runs from buildings on their side deep under the ground - and the border fence - to hideaways in Egypt.
"These tunnels are not just foxholes," said Maj. Ron Edelheit, an Israeli Army spokesman. "They are very complicated structures. They're long. They have electricity. They have trails and tracks going through them."
Stretching as far as three quarters of a mile, the underground interstate is big enough for a barnyard of livestock to be smuggled through.
That's not what bothers Israel.
"Food? Who cares; but when we talk about bombs and rockets and TNT and C4 and you name it, that terrorizes the Israeli population that surrounds it, this is not something the state of Israel can live by," Edelheit said.
To win the war, Israel says it needs to stop the smuggling of arms and explosives.
Military sources believe aerial bombardment so far has destroyed about 200 tunnels. But 100 more may still be in use.