Wudi Shell Dike Island lies north of Wudi county in Binzhou, Shandong province and borders the southwest coast of the Bohai Sea.

It is one of the three largest shell dike islands in the world, with the other two respectively located in Louisiana, the United States and the Republic of Suriname in South America.

It is also the best-preserved one, with the coexistence of both new and old shell dikes covering an area of 80,480 hectares.

Wudi Shell Dike Island has a total reserve of 360 million tons of shells, with the testaceous content reaching almost 100 percent.

A sand bed full of shells and shell fragments at Wudi Shell Dike Island [Photo/WeChat account: zhbkdd]

The thickness of the sand bed, which consists of shells, shell sand, and shell fragments, is between 2.5 meters to 5 m. Scientists believe that the sand bed was formed 2,500 years ago, serving as the rare and precious ocean marine natural relic in China and the world.

A visitor collects shells on Wudi Shell Dike Island. [Photo/WeChat account: zhbkdd]

Wudi Shell Dike Island is the transfer station for birds migrating from the Northeast Asia and the Western Pacific region. It is a fairyland for birds to spend their winter resting and breeding. It is an important base to research environmental changes, such as the evolution of the Yellow River, as well as coastlines and tides, playing an important role in marine geology, biodiversity, and wetland research.

Various birds fly to Wudi Shell Dike Island. [Photo/WeChat account: zhbkdd]

In 2003, Wudi Shell Dike Island was listed by Shandong government as a provincial-level shell dike and wetland ecosystem natural reserve. In 2004, it was further listed as a national nature reserve, aiming to better protect the shell dike, wetland ecosystem, as well as the rare and endangered birds residing there.