The system was first discovered at the end of the 19th century. It was not excavated and studied until the 1970s. By the late 20th century, archeologists' assessments were helped by satellite images and photographs taken from plane flights over the area. Archaeologists suggested that the road's main purpose was to transport local and exotic goods to and from the canyon. The economic purpose of the Chaco road system is shown by the presence of luxury items at Pueblo Bonito and elsewhere in the canyon. Items such as macaws, turquoise, marine shells, which are not part of this environment, in addition to imported vessels distinguished by design, prove that the Chaco had long-distance commercial relations with other distant regions. The widespread use of timber in Chacoan constructions was based on a large and easy transportation system, as this resource is not locally available. Through analysis of various strontium isotopes, archaeologists have realized that much of the timber that composes Chacoan construction came from a number of distant mountain ranges, a finding that also supported the economic significance of the Chaco Road.