When the sea appears on TV or in the movies， it always look endless. But do you know what it is like at the bottom of the sea？ The seafloor along the coast is a beautiful world. There are flat sand beaches and hilly mountains. On the mountains， there are "forests". All kinds of fish and shrimps¹ swim back and forth² in the "forest" and mountains. On the sand beaches， there are also different kinds of strangely shaped animals either taking a walk or playing with each other. Things are quite different at the deep bottom of the sea. It is very dark and there is not even a single thread of sunlight. Yet， many fish and animals still live there.

　　Some fish even shine！