It may be the most definitive "fact on the ground" in the 35-year history of the Israeli occupation of the Palestinian territories miles and miles of wire fences and concrete walls dividing Israel from the West Bank.
Most of the structure has yet to be built, but some Israelis are already imagining its destruction.
"I hope the day will come when they tear up the wall," says Miriam Gepner, sitting in her comfortable home on top of a hill in the West Bank. "But," she adds, "maybe it will reduce terrorism."
Ms. Gepner's ambivalence sums up Israel's as a whole. Although many Israelis don't like the fence, most see no alternative.
The Palestinian position is more unified. Because the fence is not the product of negotiations and because it will encroach into the West Bank, Palestinians see it as a unilateral imposition. "It's a method to take our land," says Ghassan Kabha, whose West Bank village will be fenced into Israel.
In light of 21 months of open conflict, the fence constitutes another symbol of the inability to resolve the Israeli- Palestinian dispute.
Just outside the Palestinian city of Kalkiliya, project manager Erez Rubenstein is supervising the construction of a 1.2-mile wall intended to prevent Palestinians from shooting at cars on a soon-to-be-opened Israeli highway that skirts the city.
It seems a structure of staggering permanence 25-foot-high concrete slabs rising into the sky. Mr. Rubenstein says Palestinian farmers have complained to him that they will no longer be able to see the sunset.
But the idea of walling off the West Bank, says Rubenstein, "is not long-term thinking. It's short-term thinking."
Even so, what worries people on both sides of the conflict is that short-term measures have a way of becoming long-term realities. For many Israelis and Palestinians, at times for very different reasons, the most troubling aspect of the fence is that they see a border in the making.
Israeli leaders have been discussing the idea since at least the mid-1990s, but it has taken the violence of the past 21 months to make it happen. In mid-June, Israel's government officially began construction of an initial, 66-mile section of the fence that will divide the northern West Bank from Israel. Set to take a year and cost nearly $1.7 million per mile, the initial phase will cover about a third of what Israelis call the "seam line" along the West Bank. Israel has already fenced off the Gaza Strip.
For the most part, the fence will be less of a barrier and more of a means for detecting any person or vehicle that crosses it through the use of radar and other electronic sensors. Conceived in conjunction with the new highway, construction of the wall around Kalkiliya began earlier, but it will be linked up with the fence.
The building of the barrier is based on the notion that Israelis and Palestinians, at least for now, must be separated. On a more practical level, most Israelis insist that a fence constitutes the best available means of keeping out Palestinian suicide bombers and other attackers.
Defense Minister Binyamin Ben-Eliezer, who initially opposed the idea and then embraced it, insists it is a "security fence" not a political or diplomatic one.
But at either end of the Israeli political spectrum, there is opposition. Right-wing Israelis object because they believe that they have a biblical and strategic mandate to retain control of at least parts of the West Bank. Building the fence, they argue, will cut off tens of thousands of Israelis who inhabit Jewish settlements and create a distinction between "true" Israelis who live inside the fence and those who don't.
From a security standpoint, critics argue that the fence won't keep out determined attackers or stop missiles or mortars.
Prime Minister Ariel Sharon, the political patron of Israel's settler movement, has gone along with the plan, but with evident misgivings. What he and Mr. Ben-Eliezer cannot overlook is the popularity of the idea as a stopgap measure.
Public opinion polls show that a majority of Israelis support the fence, even if it doesn't constitute a real answer to the conflict. "I don't think ... there's another solution," says Rubenstein, the project manager. Referring to the Palestinians, he adds: "There's no intention to stop the terror for the time being."
Many left-wing Israelis see some long-term merit in the fence, in that it may represent the emergence of a de facto Palestinian state, but others insist that the demarcation of borders should be the product of a peace agreement.
Many leftists would also like to see the settlements evacuated, a step that is virtually impossible to imagine under a Sharon government. Indeed, the government is extending the fence into parts of the West Bank in order to put some settlements on the Israeli side.
So in several areas the fence will deviate from the "green line" that marked Israel's border on the eve of the 1967 Arab-Israeli war. The Palestinians increasingly insist on Israel's full withdrawal from areas across the green line as a condition for peace.
Subtleties abound, however. The green line divides a Palestinian village called Bartaa, cutting it into a section administered by Israel and one under the civil control of the Palestinian Authority.
The head of the municipal council on the Israeli side of Bartaa, Ahmed Ibrahim Kabha, says Israeli authorities initially told him they would put the fence through the town, along the unmarked but unmissable green line.
He says he refused, petitioning the Israelis to include the entire town on the Israeli side and to provide Bartaa's Palestinian residents with permits that will allow them to work and travel inside Israel. Israel's Defense Ministry supports his account.
"This wall will not be a border between a Palestinian state and Israel," Mr. Kabha says, nicely articulating Israel's position. "It's just to protect against suicide bombers."
Asked whether he worries about being accused of being a traitor to the Palestinian cause, he says: "The question of borders and land doesn't matter to us. What we are looking for is peace and reconciliation between the two sides."
Across the green line, Ghassan Kabha, who heads the village on the Palestinian side, rejects the idea that Israeli authorities take their cues from their citizens of Palestinian origin. "The Israelis act as if they are God," he says. "I don't think Ahmed Ibrahim or I could influence Israeli opinion."
He rejects the idea that being included in the fence might improve living conditions for all the residents of Bartaa. "As a Palestinian, it is not important to have money or an easy life," he says. "The most important thing for us is to have freedom and democracy and dignity.... The only thing that can do that is the end of Israeli occupation."
Salit, where Miriam Gepner lives, is one of the Jewish settlements that Israel will include on its side of the fence. But Gepner says it never made much difference to her whether she would have to cross the fence to get home or not.
For one thing, she says, "we don't know how permanent it's going to be." For another, she continues, alluding to friendships she has tried to maintain with her Palestinian neighbors, it is not the physical barriers that worry her so much. "I'm concerned about the fences in the heart."
To Keep In: East Germans
Length: 103 miles (surrounding West Berlin)
The Berlin Wall was far more than a physical barrier separating East and West Germany. As the physical embodiment of the Iron Curtain, the wall quickly became the central symbol of the ongoing cold war.
Erected almost overnight by the Soviets and East Germans, the Wall was meant to stem a tide of migration from the East to the West. Its concrete barriers, guards, electric fences, and armed checkpoints slowed the flow, but almost 200 people were killed while attempting to defect; thousands more made it across, or were stopped in the process.
As a touchstone for Western political rhetoric and the icon of a divided Europe, the symbolic wall took on epic proportions. But the legacy of the physical wall, finally torn down in 1990, is far from trivial in its own right; German leaders are still working today to fully reunite a country once divided by guns and barbed wire.
To Keep Out: Troops from each side
Length: 151 miles
Described by former US President Bill Clinton as "the scariest place on earth," the Demilitarized Zone (DMZ) that divides the two Koreas is a cold-war legacy that has yet to thaw. Established under the 1953 armistice that put the Korean War on hold, the DMZ bristles with land mines, towers, razor wire and nearly two million soliders from the two Koreas. More than 37,000 US troops are stationed in South Korea.
While effectively chilling the armed conflict that once threatened to provoke a world war, the barrier has kept the hermit nation of North Korea almost totally isolated from its southern neighbor. If the peninsula reunites, the cost of decades of North Korean isolation will weigh heavily on its southern neighbor and the international community. In the meantime, the frontier is one of the world's touchiest; if North Korean troops cross the DMZ in force, the United States is, under a 1954 agreement, automatically committed to war.
Fortified: The 20th century
To Keep Out: Illegal immigrants and workers from Latin America
Length: 2,000 miles
An extension of the natural barrier created by the Rio Grande River, the border between the United States and Mexico is the front line of a massive economic and cultural struggle. Mexican workers and families, seeking the relatively plentiful and rewarding jobs inside the United States, risk confrontation with US Border Patrol agents and the INS as they cross the border by the hundreds of thousands.
A greatly beefed-up US security presence along the border has decreased the numbers of immigrants trying to make the increasingly difficult crossing, and fatalities, while still numerous, have decreased in recent years.
But the crossing still takes a harsh human toll; every year, hundreds of immigrants die in the scorching desert or drown while crossing the river. On July 4, the Mexican Foreign Department released a statement saying 167 migrants of all nationalities (117 of them Mexican) died trying to cross the US border in the first half of the year. A total of 210 Mexicans died in the same period in 2001, and 283 during the first half of 2002.
Built: Around 220 BC
To Keep Out: Invaders from the north
Length: roughly 4,500 miles
Knitted together from a rugged patchwork of far smaller improvised barriers and built over the course of a millennium, the Great Wall of China remains one of humanity's most ambitious feats of engineering.
Historians estimate that building the Great Wall cost over a million lives, and the equivalent of hundreds of billions of US dollars. While pricey, the wall kept northern invaders at bay with varying and still-debated amounts of success until the Mongol conquests in the 13th and 14th centuries.
For many, the Great Wall embodies China's relationship with the outside world. Its strength and sweep are seen as the achievements of a powerful, mature civilization. But to much of the outside world, the Great Wall is the icon of a fortress mentality.
Wall profiles by James Norton