A few weeks ago Egyptian soldiers discovered a 2,400-foot underground pipeline used to smuggle fuel into Gaza. Black market fuel has now become a lucrative business due to the closure of the coastal territory.

This followed a senior Egyptian security official reporting that Egyptian police had recently uncovered 20 underground tunnels and seized thousands of gallons of fuel being smuggled under the border. During the discovery four smugglers were arrested after a heavy exchange of gunfire.

At the beginning of this month, five smugglers were killed when Egypt blew up another tunnel exit, suffocating them inside.

The Egyptian authorities claim they destroy on average one tunnel a day, but the smugglers contend that the destruction might delay shipments but won't halt them as they can quickly dig new tunnel entrances by branching out from the main passages which have been blown up.

Israel assesses there to be more than 100 underground tunnels importing everything from automatic weapons, contraband drugs, clothing and laptop computers to animals and even humans.

The town of Rafah in the southern Gaza strip opened its first zoo, "Heaven of Birds and Animals Zoo" in June of this year.

All the animals including monkeys, lions, gazelles and parrots were drugged, put in sacks, and then smuggled in.

Shadi Fayiz, the 23-year-old manager of the zoo, said the lions were smuggled in as cubs and cost him $3,000 each. Altogether the zoo set him back $40,000.

"Without the tunnels, I couldn't have done this," he said.

In addition to helping ease the economic boycott on Gaza, the tunnel-smuggling business has been good for associated side-industries and enterprising entrepreneurs and middlemen.

Middlemen coordinate demands between Gaza traders and Egyptian suppliers. One trader, who wanted to remain anonymous for fear of being caught, told AP that he would receive orders from the traders for specific products and would then relay those orders to Egyptian businessmen.

He would then assess the quickest and easiest way to "import" the goods which included food and other groceries, as prices varied according to tunnel size and how much was transported through them.

"Some tunnels charge $100 a box, some just $70. You have to compare prices," he said. The tunnels also vary in size from 100 feet-long to a mile in length. Some are small enough to only drag boxes through or high enough to allow people to walk through.

Smuggling persons wanted by the Israeli authorities can be particularly lucrative, earning the tunneler up to $10,000.

Although the tunnelers can make up to $12,000 on completion of the tunnels, digging them is hard, dangerous and unpleasant work in hot and stifling conditions with limited supplies of oxygen. And there is always the risk of death from collapses or if the tunnel is blown up by Egyptian or Israeli security forces.

They also face possible arrest from Hamas and Egyptian authorities. Hamas leaders are not against the tunnel smuggling, but want to control it for tax purposes. However, they have outlawed the smuggling of weaponry as only their security forces are permitted to carry arms.

Included in this lucrative business are the people whose houses or property cover the exits and entrances to the tunnels. These points are found in homes, businesses and sometimes even animal corrals.

Smuggling is not new to Gaza and its border crossing with Egypt's Sinai, but it has never been as active or as competitive as currently following the siege on the Strip.

Bedouin tribesmen have been actively engaged in the smuggling for decades as a means of ensuring a livelihood. The Egyptian security sources would use camels to intercept contraband smuggled by the Bedouins, but nowadays they rely on vehicle patrols.

And while this innovative and enterprising way of beating the embargo has helped to somewhat ease the plight of Gazans, it is still a long way from meeting even the most basic needs of most of the impoverished 1.5 million people who live in the Gaza strip.

As Hamas spokesman Sami Abu Zuhri put it: "A tunnel can bring in a mobile phone, but it can't bring in raw materials," such as cement, building materials, and sufficient gasoline and other fuel, which are all in short supply. Because of that Gaza is paralyzed."