'Missing' cultural sites number 23,600

Historians have sounded the alarm after 23,600 registered cultural sites apparently "disappeared" in three years.

The sites were largely erased because of development - swept aside by construction work and infrastructure projects including reservoir and road projects - says a national survey carried out by the State Administration of Cultural Heritage (SACH), the country's top relics protection authority.

SACH has been working on the inventory since 2007 and hopes to have a full list of China's historical sites - including ancient tombs, temples and architecture - by 2011.