The Maeslantkering ("Maeslant barrier" in Dutch) is a storm surge barrier on the Nieuwe Waterweg, in South Holland, Netherlands.

Part of the Delta Works, the barriers are controlled by a supercomputer, and automatically close when Rotterdam (especially the Port of Rotterdam) is threatened by floods.

Maeslantkering has two 210 meters long barrier gates, with two 237 meters long steel trusses holding them.

When closed, the barrier will protect the entire width (360 meters) of the Nieuwe Waterweg, the main waterway of Port of Rotterdam.

According to en.wikipedia