A sedimentary rock, unearthed from the Gangshen Ruins in suburban Shanghai's Maqiao town, is borrowed from the collection of Shanghai Science and Technology Museum. Dated from 60,000 years ago, it illustrates how the ocean and waves pushed sand and remains of shellfish together to form the ancient coastline of Shanghai.

Also on exhibition at PSA is the replica of a sand boat, one of the most commonly used boat forms in the city. The flat bottom of the boat made it unlikely to be grounded near the sandy bank of Shanghai, and it sailed steadily on the complex waterways of the Yangtze River Delta. The boat witnessed Shanghai's urban development through the past century. In 1990, the city introduced a new insignia consisting of the sand boat, magnolia blossom and turbo propeller.

If you go

Bodies of Water: the 13th Shanghai Biennale

11 am-7 pm, Tuesday-Sunday. Last entry no later than 6 pm.

April 17-July 25. 678 Miaojiang Road, Huangpu district,

Shanghai.www.powerstationofart.org