Chongming Island, just north of Shanghai, is the world’s largest sandbar. Formed by the deposit of millions of years of Yangtze River silt, its shoreline is constantly evolving. Even though the recently completed Three Gorges Dam has blocked the downstream progress of much of the river’s sediment, Chongming’s eastern end continues to lengthen by about 150m per year.

With less than 700,000 people scattered over more than 1,000 square kilometres, Chongming has room to roam. The local government has been busy promoting the island’s ecological attributes, hoping that bicyclists and birdwatchers will contribute to its development as a tourist destination for Shanghai’s city dwellers, starved for nature. Dongping National Forest Park (5933 8028) offers camping, rock climbing, and grass skiing. Dongtan Nature Reserve , on the island’s eastern edge, provides a crucial waypoint and wintering ground for migratory waterbirds.

A few kilometres from the nature reserve, construction has begun on the world’s first eco-city. The green community of Dongtan will permit only non-polluting vehicles, recycle all of its wastewater, and generate all of its own power through wind, solar and the burning of rubbish. Planners expect the city’s population to reach 500,000 by 2050.

Access is currently by ferry from Shidongkou in Baoshan district, which can involve waits of an hour or more in addition to the hour-long passage. The Changjiang tunnel and bridge project, scheduled for completion in 2010, aims to cut the travel time from Shanghai to 40 minutes. Call the Chongming Island tourist information centre on 6969 5888 for the latest developments.