Both Israelis and Palestinians claim the historic city as a future capital, and neither are prepared to give it up.
So when, early in his Presidency, Donald Trump floated the idea of recognising Jerusalem as the capital of Israel, it was hugely controversial.
Now, with tensions across the region running high, he is set to announce the move in a major speech.
Listen to the interview with Ansheln Pfeffer, Jerusalem correspondent @ The Economist on the ABC RN Drive program