A port is a sheltered place along the sea or river where boats can stop safely and perform loading/unloading operations. It consists of breakwaters to protect berths from waves, access channels, signs, docks, and harbors for boats to wait safely. The land area contains facilities to support goods operations, storage, and regulate maritime-terrestrial flows. A port sometimes hosts basic industries like steel mills or shipyards. It provides boat services like towing and fueling, merchandise services like customs and freight, and land transport services. Special types of ports include leisure ports for recreational boats, shipyards for vessel construction and repair, and fishing ports for unloading and selling perishable fish goods.