Stone rollers tell story of sacrifice

Hundreds of thousands toiled day and night to construct four air bases for US military

Visitors to the Jianchuan Museum Cluster in Dayi county in Sichuan province show a keen interest in five huge stone rollers on display in the largest private museum in China.

Weighing from five to 15 metric tons, they have been rated as first-class cultural relics by the National Administration of Cultural Heritage, thanks to their role during World War II.