Bethlehem is not only famous as the birthplace of Christ, but also for its street art along the wall that Israel has built despite the International Court of Justice ruling that the wall is illegal according to International law.
The nature of street art means that the graffiti on the wall is forever changing, mostly to convey current political messages. One of the most famous graffiti artists who has visited the West Bank and Gaza several times is Banksy. He famously claims that Palestine is the "ultimate activity holiday destination for graffiti writers".
Street art can be found all over Palestine and espeically along the Wall between Israel and the West Bank. Bethlehem is a good place to start.