Harbours are coastal or estuary facilities where commercial, fishing and leisure vessels can enter, berth and access services. Harbour businesses and operators may manage quays, pontoons, moorings and visitor berths, as well as vessel movements, navigation channels and harbour safety. Depending on the port, services can include pilotage, tug assistance, cargo handling, passenger facilities, boat launching, fuel, maintenance and the collection of waste from vessels. Some harbours also provide facilities for fishing fleets, ferries, water-based businesses and local maritime activities. Lighthouses are fixed structures that provide visual aids to navigation, helping vessels identify coastlines, hazards and safe routes. Their lights may use different colours, patterns or sectors to convey navigational information, and some sites also have fog signals or other aids.