This structure found along beaches is built out of concrete to protect a town from rising water.

The first sea wall was first constructed by the Romans in the 1st century B.C.E. The structure used, volcanic sand which hardened and stayed hard even when exposed to water. Sea walls are still in use today around the world and are built from reinforced concrete.

Asked by Jennifer Sinclair · Last updated 5 years ago · 10.9K views · SOURCE