Three days after a massive earthquake devastated the Haitian capital, Port-au-Prince, the number of casualties is still unknown. The International Red Cross is estimating at least 50,000 people are dead. But as BON's Mark Dreyer reports. International rescue workers – including a team from China – are on the ground and have begun their sometimes harrowing work.

The scenes are horrifying. Total devastation as far as the eye can see. Port-au-Prince, once home to 3 million Haitians, is fast becoming an open graveyard. An estimated 90% of buildings have collapsed. Hospitals, which should have treated casualties, have crumbled across the city. Even the presidential palace, government buildings, the UN Mission headquarters and cathedrals have not escaped the devastation.

International aid agencies and governments from across the globe have pledged aid and assistance. But the country's infrastructure is so badly damaged that much of the aid cannot get to those who need it.Still international relief efforts are gradually making headway. A team of 50 Chinese aid workers has been in Port-au-Prince since Thursday.