A stone cap that was used to gouge eyes of serfs in a Lhasa prison in old Tibet is on display at an exhibition marking the 50th anniversary of the Democratic Reform in Tibet Autonomous Region in Beijing, Feb. 25, 2009. (Xinhuanet Photo)

A boy watches a simulated scenario featuring serfs burning feudal documents produced in old Tibet after the Democratic Reform at an exhibition marking the 50th anniversary of the Democratic Reform in Tibet Autonomous Region in Beijing, Feb. 25, 2009. (Xinhuanet Photo)