It could be the biggest chance in years for the Palestinian faction Fatah to stage a comeback.<br /><br />On Tuesday, it will convene its first party congress in two decades - in an effort to revive a divided and demoralised movement. <br /><br />Delegates will be travelling from far and wide. But Fatah members from Gaza face a ban imposed by rival Hamas.<br /><br />Al Jazeera's Ayman mohyeldin explains.
