This document defines and describes various landforms and bodies of water. It explains that a bay is an area of water bordered by land on three sides, a gulf is a larger body of water partly surrounded by land, and a peninsula is a piece of land surrounded by water on three sides. It also defines deltas, isthmuses, straits, lakes, mountains, hills, plains, plateaus, rivers, waterfalls, fjords, valleys, glaciers, archipelagos, seas, and oceans.