An aerial lift is a means of cable transport in which cabins, cars, gondolas or open chairs are hauled above the ground by means of one or more cables. Aerial lift systems are frequently employed in mountainous territory where roads are relatively difficult to build and use, and have seen extensive use in mining. Aerial lift systems are relatively easy to move, and are and have been used to cross rivers and ravines. In more recent times, the cost-effectiveness and flexibility of aerial lifts has seen an increase of gondola lift being integrated into urban public transport systems.