A bay is a large body of water in the land next to a sea or lake between two headlands. The waves coming to the shore in a bay are usually constructive waves, and because of this, many of them have a beach. A bay may be metres across, or it could be hundreds of kilometres across. A large bay is often called a gulf, sound, or bight. A bay often contains beaches.
Bays form where weak rocks, such as sands and clays, are eroded, leaving bands of stronger rocks, such as chalk, limestone, or granite, forming a headland, or peninsula. Bays are formed when there are parallel sections of softer and harder rock perpendicular to the coast.
