A photo taken on August 11 shows China's zero sea-level marker at Silver Sea Big World in Qingdao, east China. The marker is a benchmark that follows international standards for observing changes in the country's tides, sea level, heights and elevations. The site was built in May 2006. [Photo: Xinhuanet]
A boy plays at China's zero sea-level marker in Qingdao on August 11, 2009. [Photo: Xinhuanet]
A red stone ball in an underground drywell in Qingdao serves as another similar zero sea-level marker. [Photo: Xinhuanet]
