The Sinai's desert pathways are the supply routes for one of the world's most notorious smuggling operations, feeding, clothing and arming the people of the Gaza Strip, writes Jason Koutsoukis in Al Arish, Egypt.
We met our contact in Al Arish, the Mediterranean resort town in the northern Sinai located about a 45-minute drive from the Egypt-Gaza border.
Insisting on the sort of secrecy that would not have been out of place in an episode of Get Smart, the man, who called himself Abu Saad, emerged from a mobile phone shop near the Hotel Sinai Sun and got into the rear seat of our vehicle.
Given what it took just to get to Al Arish, talking our way through countless police checkpoints and roadblocks, perhaps his demand for the utmost discretion didn't seem unwarranted.
Directing us through Al Arish's tightly packed inner-city streets, barely wide enough to fit a single car, we eventually arrived outside a small warehouse about the size of a single-fronted house.
Leading us inside, he revealed a room that was stacked to the ceiling with contraband of the most lacklustre kind: vegetable oil, dry biscuits and several hundred cartons of cigarettes.
''All for Gaza,'' murmured Abu Saad. ''Everything you see in this room, will be sold to people in Gaza.''
Abu Saad took us to several other warehouses that he managed on behalf of a family he said was connected to the Tarabin people, a Bedouin tribe that controlled a slice of territory that extended all the way up to the border.
Of the 360,000 people who live in the Sinai, about 200,000 are believed to be Bedouin, literally ''men of the desert'', who originated on the Arabian peninsula. About 15 Bedouin tribes now share the Sinai along strict, agreed lines of demarcation.
''Most things come from Cairo,'' said Abu Saad. ''We store everything here until we can move them into Gaza.'' Abu Saad estimated that, altogether about 100 people worked full-time in the family operation.
''Many people here have family inside Gaza, there are very strong connections between us, so that's how we find each other to do business.'' He insisted that the only things the clan were specifically banned from dealing with were weapons.
''This is very, very much controlled by Hamas. Only Hamas knows about this, they have their own people over here.''
Flanked by the Mediterranean Sea, the Gulf of Suez and the Gulf of Aqaba, the Sinai Peninsula is a sliver of desert sandwiched between the African and Asian continents.
Controlled over the last 100 years by Britain, Egypt, Israel, and, since 1982, by Egypt once again, the Sinai is one of history's most fabled crossroads.
According to the Bible, it was across the Sinai that the Israelites trekked in search of the promised land, while it was upon the summit of Mount Sinai near Red Sea that Moses received the Ten Commandments.
Yet today the Sinai's desert pathways are the supply routes for one of the world's most notorious smuggling operations that feeds, clothes and arms the people of the Gaza Strip.
Everything that money can buy in Gaza owes its provenance to Egypt and the sandy byways of the Sinai.
Petrol, electronic goods, livestock, small cars - you name the item and the chances are that buyers and sellers will be able to find a match in a tunnel somewhere beneath the 12-kilometre stretch of border that Egypt shares with Gaza.
Commodities trading is one thing, but for Hamas, the militant Islamic movement that has ruled Gaza since 2007, the Sinai's smuggling routes have become its only connection to the world outside.
In the 12 months since Israel launched Operation Cast Lead - a military offensive that involved more than 3000 air raids plus a two-week ground invasion - Israeli intelligence suggests that Hamas has been able to successfully rearm itself.
Not just with bulk explosives that are packed into the heads of the homemade Qassam missiles that Hamas has fired at southern Israel, but with military grade Katyusha and grad-style rockets that have the range and accuracy to hit large Israeli cities such as Ashdod, Beersheba and Ashkelon that are home to several hundred thousand people.
Millions of rounds of ammunition, assault rifles, hand guns, anti-tank weapons and other arms are also believed to have been smuggled through the tunnel network.
Last month, Israeli officials produced evidence of what it believed was the test-firing by Hamas of a new style of rocket that had a range of about 60 kilometres.
If true, that would give Hamas the ability to target Tel Aviv. ''We know they are keeping on smuggling in rockets and other weapons, because we can see a lot of what is coming in,'' says the retired major general Giora Eiland, who oversaw Israel's military withdrawal from the Gaza Strip in 2005.
''That is why we keep hitting specific tunnels today from the air every so often, because we are fairly certain of what we can see going into them,'' Eiland, a former director of Israel's National Security Council, told the Herald.
According to Eiland, the smuggling routes to Gaza are well defined. Mostly from Iran, via the Red Sea and up the Suez Canal to Egypt's Mediterranean port cities of Port Said and Damietta.
''From there, there are many ways to get across the desert, but in the end everything converges on Rafah,'' Eiland said.
The only way to prevent smuggling, Eiland believes, is to build a wall that encircles Rafah and establishes a buffer between it and the rest of the Sinai.
''Rafah is densely populated, there are many places to hide, so it is difficult to stop the smuggling once the goods get there. The key is stop things getting into Rafah in the first place and that can be done by building a fence around Rafah.''
Last week, Egypt revealed that it was commencing work on an underground wall made of steel along its border with Gaza to try to curtail the smuggling by preventing people from digging tunnels.
The steel wall is reportedly being built with the help of British and American military engineers.
Yet spend a little time in the southern Sinai, at one of the multitude of bars and nightclubs that have mushroomed along the Sinai's Red Sea coast over the past decade such as Pacha in Sharm el-Sheikh, and it doesn't take long to work out what the Sinai's other exports are.
Women working as prostitutes, most likely Russian or elsewhere in Eastern Europe, use the Sinai's Red Sea resorts as a first stop on the way to Israel and Middle Eastern countries.
The Sinai is also a major supplier of drugs, such as locally cultivated varieties of marijuana and opiates, to the region.
According to a 2004 report published by the US embassy in Israel, Egypt serves as the country of destination and transit for trafficking victims.
''It has been asserted that Egypt serves as the most common country of transit for trafficking to Israel,'' the report said.
''Victims are flown to cities such as … Sharm el-Sheikh and Cairo, from which they are transferred to Israel through the Sinai Desert.
Women are smuggled in groups, together with goods, drugs, weapons and migrant workers.''
With the 230-kilometre border that stretches across the Sinai peninsula from the Mediterranean to the Gulf of Aqaba apparently porous all the way along, it seems that it will take more than the prospect of an underground steel wall to prevent goods and services from flowing across it.
