Hu warns Chinese Communist Party
The Chinese Communist Party is celebrating its 90th anniversary on 1 July 2011. Today the party has almost 80 million members, which makes it the biggest political party in the world.
The BBC's Chris Hogg takes a look around a museum which is housed in the building where the first congress of the party was held in 1921.
The Shanghai museum includes the room where the first secret meeting, involving just 13 delegates, took place.