There are two types of lighthouses: ones that are located on land, and ones that are offshore. Offshore Lighthouses are lighthouses that are not close to land. There can be a number of reasons for these lighthouses to be built. There can be a shoal, reef or submerged island several miles from land. Lighthouses mark dangerous coastlines hazardous shoals, reefs, rocks, and safe entries to harbours. They also assist in aerial navigation.
