Sichuan: lessons learnt?
Last year's earthquake in China's Sichuan province is believed to have killed more than 80,000 people.
Now, the authorities have, for the first time, given an official figure for the number of schoolchildren left dead or missing; they put the toll at 5,335.
In the aftermath, the authorities faced awkward questions about why so many schools in particular collapsed, when buildings around them stayed standing.
Many parents blamed shoddy construction and neglect.
The rebuilding effort has been proceeding quickly, but have the Chinese authorities implemented the lessons learnt about the quality of public building?
Ai Weiwei is a renowned architect and outspoken critic of his government.
First broadcast 7 May 2009