The Great Inka Trail, Qhapac Ran or Inka fian, was a complex road, administrative, transportation and communications system that was also used as a means to demarcate the four basic divisions of the so-called Inka Empire. The development of this system considered three basic characteristics: gathering of population, gradient of the ground, and natural composition of the soil. A main path started in Cusco towards each of the four "suyos" (regions). The roads were inscribed in the geography of the State. The system comprised almost all the territory of the Andes, including nowadays Perd, Bolivia, Ecuador, Argentina and Chile. It was formed by four main roads clearly recognizable, and many secondary roads which still are in the process of being identified (some of them may be identified by natural and/or artificial indicators). Great part of the system was built over more ancient roads. It presented a series of architectural structures, each of which had different and specific :ftmctions. Bridges and pulley bridges used over rivers were built to save the continuity of trails along the rugged geography of the Andes. Beside the roads, the transportation system was composed of other important architectural elements such as "tampus" (lodging places with storage facilities), "kanchas" (rectangular spaces surrounded by walls enclosing several structures), "kallankas " (large rectangular buildings within the kanchas, probably used as rest areas), storage facilities (warehouses) and other minor architectural elements but not of a lesser importance, such as "apachetas ", "chaskiwasis ", sacred sites, control places for people and products and other evidences such as landmarks, boundary marks and "huancas ". It is important to emphasize that the purpose of the transportation system was also to connect Cusco with the main administrative centers of the Inca empire, such as Vilcashuarnan (Ayacucho), Tambo Colorado (Ica), Incawasi and Pachacamac (Lima), Xauxa (Junin), Huanuco Pampa (Huanuco), Caxamarca (Cajamarca), Tomebamba and Ingapirca (Ecuador), Pasto (Colombia), Cochabamba (Bolivia), San Pedro de Atacama (Chile), and La Paya (Argentina). The Inca transportation system had to conform to a very diverse geography, from the high mountains of the Andes to the plains of the coastal region, from the driest regions of the desert to the small and most fertile valleys of the Andes. The system remains as an evidence of the ingenious constructive technology which was adapted to this difficult geography. As the trails gain access to different landscapes a varied of natural settings complement this cultural heritage.