Choked off from the outside world under a tight Israeli blockade; Gaza smugglers boast about the hundreds of tunnels breaking the siege and connecting the impoverished strip to neighboring Egypt.
Gazans in desperate need of goods, such as food and medicine, say their city is rife with tunnels and smuggling has now become a lucrative business in the densely populated area.
"The ground at Rafah is a real Swiss cheese. If there were an earthquake the whole lot would cave in," the boss of one of the tunnels told AFP.
"People come from everywhere to find work: Gaza, Jabaliyah, Deir al-Balah … This tunnel alone keeps 15 families alive," he said.
The exact number of tunnels is impossible to verify but the rapid growth of excavation work is plain for all to see.
At 10 in the morning in Rafah, the only sounds come from the nearby border, where the grinding of motors draws attention to smugglers busy digging more passages beneath this sandy frontier.
The presence of scores of tunnels is revealed by plastic huts camouflaging their entrances and by the heaps of earth visible along the 14-kilometre (8.5-mile) demarcation line.
"It is a growth industry because of the blockade of Gaza and the closure of frontiers," said Abu Khaled, in charge of one of the sites, where tunnelling began 10 days ago.
Around his tent alone, three more tunnels are under construction.
Not very long ago it was difficult to meet smugglers or talk to them, but now they operate openly and with everyone’s knowledge and they are not bothered by anyone except, they say, when it comes to paying taxes to the Hamas government, which controls Gaza.
The smugglers’ brazenness compares with the continuing secrecy around tunnels, which Israel suspects of being used to bring in weapons.
"We work every day, round the clock, six people by day and six people by night," said Abu Khaled, a former member of Force 17, the elite Palestinian group in charge of protecting president Mahmud Abbas.
"From time to time, Hamas passes by to tell us it is forbidden to traffic in weapons or hashish," he said as he helped an earth-spattered young worker to fill in a 20-metre (67-feet) deep pit.
Abu Khaled says Hamas also takes "its percentage" on the products that enter the Gaza strip, where crossings with Israel remain closed since the Islamists took power in June last year.
As the blockade has continued, the number of tunnels has multiplied, with the blessing of Hamas, which sees them as a way of breaking the Israeli siege.
With unemployment at record levels in Gaza, tunnel owners have no difficulty finding workers despite the danger of death at any moment from the collapse of a passage, lack of oxygen or operations by the Egyptian army.
In the shed of Majid Arbi’a, formerly director of a cement works that has closed for lack of raw materials, most of the laborers are students.
In other places they might fund their studies by being waiters or beach attendants. In Gaza, they dig tunnels at $500 for 100 meters completed.
"There is no work anywhere and I need money," said 29 year-old Yussef, a photography student at the University of Deir al-Balah, in the center of Gaza.
"Everyone who works here is at university like me. Some are even working on their doctorate," Yussef said.
(AlArabiya.net and AFP)