What is the fence?
In fact, it's part-wall, part-fence. Most of its 440-mile length is made up of a concrete base, topped by five metres of wire. Ditches and rolls of barbed wire are on either side of the fence.
Why is Israel building it?
It says the fence will stop Palestinian would-be suicide bombers from entering Israel and attacking Israeli people.
What are the main objections to the fence?
Palestinian land has been taken away to build the fence and hundreds of Palestinians have been cut off from their land, schools or places of work.
What does Israel say about the fence?
It says the fence is purely for security. It says it has nothing to do with a future border and there's nothing to stop the fence being removed once the two sides agree who's having what land.
What does the United Nations think about the fence?
It's not happy. It's issued a report saying the fence is illegal. It has warned that thousands of Palestinians could end up as refugees if they end up cut off by the fence.