A quay is a broad word used to define a maritime structure used for mooring or tying-up of vessels, as well as loading and unloading of products and passengers, for the purposes of this chapter. It is often parallel to the beach. A pier, sometimes known as a finger jetty, is a quay that extends into the water. Both quays and piers are used by fishermen to shelter their boats from wind and weather. The main function of a quay is to provide a stable work platform for loading and unloading vessels, and to protect them from damage caused by high waves and tides. Quays can be constructed out of rock, concrete, timber, or steel. The choice of material depends on how much use the quay will get and how much weight it will have to support. Heavy machinery needs strong foundations, so concrete is usually preferred over other materials when building bridges or heavy structures such as factories. Quays can also be used for recreational purposes. They can be built out of rock if you want to create a small beach area, or out of wood if you want to add some color to your yard. There are many different types of designs available and it's up to you to choose what kind you want to build. Finally, quays can be used as part of a port infrastructure. This includes facilities like warehouses, storage tanks, and equipment sheds that are needed before ships can be loaded or unloaded.