The unique purpose of transportation is to overcome space, which is shaped by a variety of human and physical constraints such as distance, time, administrative divisions and topography. Urbanization, multinational corporations, the globalization of trade and the international division of labor are all forces shaping and taking advantage of transportation at different, but often related, scales. Consequently, the fundamental purpose of transport is geographic in nature, because it facilitates movements between different locations. Transport thus plays a role in the structure and organization of space and territories, which may vary according to the level of development. In the 19th century, the purpose of the emerging modern forms of transportation, mainly railways and maritime shipping, was to expand coverage with the creation, expansion and consolidation national markets. In the 20th century, the objective shifted to selecting itineraries, prioritizing transport modes, increasing the capacity of existing networks and responding to the mobility needs and this at a scale which was increasingly global, with its own space of flows. In the 21st century, transportation must cope with a globally oriented economic system in a timely and cost effective way, but also with several local problems such as congestion and capacity constraints.