A land lighthouse is simply a lighthouse constructed to aid navigation over land, rather than water. Historically, they were constructed in areas of flatland where the featureless landscape and prevailing weather conditions (e.g. winter fog) might cause travellers to become easily disorientated and lost. In such a landscape a high tower with a bright lantern could be visible for many miles.
Due to general improvements in transport and navigation throughout the 19th century, land lighthouses became almost totally obsolete as aids to travellers in remote places.