For years, Hamas has avoided an Israeli blockade of Gaza by smuggling weapons and other goods through tunnels from Egypt.
But now, Egypt is building an underground wall that could stop the smuggling.
With Egyptian soldiers standing guard, construction workers are pounding steel beams into the soil along Egypt's nine mile border with the Gaza Strip.
Palestinian men and boys have been working around the clock in the tunnels, smuggling weapons, explosives, cigarettes, food, gasoline--even terrorists.
Israeli leaders have also complained about the threat the tunnels poses, but Egypt has done little about it until now.
Israel claimed Hamas boosted the smuggling of explosives dramatically when it took over the Gaza Strip three years ago.
"Before Hamas came to power, three to four tons of explosives have been smuggled through these tunnels," said Israeli Army spokesperson Avital Leibovich. "After Hamas came to power, we are talking about at least about a hundred tons of explosives were smuggled inside Gaza every year."
The new wall in the desert could cut off all of the traffic in the 400 tunnels and put more pressure on Hamas to ease up on its pledge to destroy Israel.
Leaders in Gaza say the tunnel is their lifeline and that Egypt is caving in to Israeli and American pressure.
"People, they want to live and they want something to eat. They may do everything they can." Hamas spokesman Ehab Ghussein said.
Mosa, a teenager who works in the tunnels, said he would die from hunger if he didn't have his job.
'We are asked to go through the tunnels to the Egyptian side. We deliver the money, get the goods, and bring the goods back to Egypt," he explained.
A 12-year-old boy does grueling work, making about $10 for his 12-hour shift.
"I go nine meters deep and we walk underground for 400 meters," he said.
On the border town of Rafah, Gazans have traditionally hidden some of the tunnel entrances disguised as greenhouses. Disguising them is a lucrative business.
"As I know maybe only about 15,000 people work in these tunnels," Rafah Mayor Issa Nashar said. "They bring what the Gaza Strip needs for materials, about $1 million every day.
Last week, hundreds of Gazan women marched at the Egyptian border to protest the tunnel barrier. This time the Egyptian government seems intent on shutting down the traffic.