The South China Sea's rich history of maritime trade and its unexplored cultural heritage, especially shipwrecks, single it out as needing protection, Unesco officials say. These wrecks could throw a new light on history, according to Etienne Clement, Unesco's representative in Cambodia. Objects and inscriptions could offer a glimpse into the lives of people dating back thousands of years. About 50 shipwrecks have been identified in Hong Kong waters and nearly half are considered worthy of further study. Mr Clement was in Hong Kong for a three-day workshop on the protection of underwater cultural heritage in the Asia-Pacific region, attended by about 100 underwater-archaeology experts from 20 countries. 'The objects discovered can be exhibited or they can stay in the sea. One could also transform shipwrecks for the tourism trade,' Mr Clement said. Unesco defines underwater cultural heritage as 'all traces of human existence having a cultural, historical or archaeological character which have been partially or totally under water, periodically or continuously, for at least 100 years'. One of the organisers of the workshop, David Lung Ping-yee, also the council chairman of the Lord Wilson Heritage Trust, said he hoped it would be the first step to developing Hong Kong into a 'dragon head' of heritage conservation. Unesco and the Antiquities and Monuments Office (AMO) also helped organise the workshop. Professor Lung said Hong Kong's location in the Pearl River Delta, its expertise in heritage conservation and its internationalism made it an ideal place to be developed into a conservation hub. But he said this depended on the city's resources and support from the government. According to the AMO, 49 shipwrecks have been identified in Hong Kong waters, of which 22 are recommended for further study. Mr Clement said interest in underwater cultural heritage had been aroused after the wreck of the luxury cruise liner Titanic was discovered in September 1985. 'The [exploration of] the Titanic showed that [we are capable of] going to deep sea levels,' he said. The Titanic's discovery inspired people to talk about co-operating internationally to protect underwater cultural relics, leading to the 2001 Convention on the Protection of Underwater Cultural Heritage. Mr Clement, who was involved in drafting the convention, said it aims to address the growing concern that places of underwater cultural heritage, especially historic shipwrecks, have been looted with relics being illegally exported and sold without proper excavation. 'A few thousand [of these underwater sites] have been looted already,' he said. Bulgaria and Panama are the only countries to have ratified the convention but Mr Clement is optimistic the target of 20 countries will sign up, enabling the convention to come into force within three years.