the University of New Mexico and the National Park Service. A number of multi-disciplinary research projects, archaeological surveys, and limited excavations began during this time. The Chaco Center extensively surveyed the Chacoan roads, well-constructed and strongly reinforced thoroughfares radiating from the central canyon. The richness of the cultural remains at park sites led to the expansion of the small National Monument into the Chaco Culture National Historical Park on December 19, 1980, when an additional were added to the protected area. In 1987, the park was designated a World Heritage Site by UNESCO. To safeguard Chacoan sites on adjacent Bureau of Land Management and Navajo Nation lands, the Park Service developed the multi-agency Chaco Culture Archaeological Protection Site program. These initiatives have identified more than 2,400 archeological sites within the current park's boundaries; only a small percentage of these have been excavated. Management Chaco Culture National Historical Park is managed by the National Park Service, a federal agency within the Department of the Interior; neighboring federal lands hosting Chacoan roads are controlled by the Bureau of Land Management. In the 2002–03 fiscal year, the park's total annual operating budget was $1.434 million. The park has a visitor center, which features the "Chaco Collection Museum", an information desk, a theater, a book store, and a gift shop. Prior to the 1980s, archeological excavations within current park boundaries were intensive: compound walls were dismantled or demolished, and thousands of artifacts were extracted. Starting in 1981, a new approach, informed by traditional Hopi and Pueblo beliefs, stopped such intrusions. Remote sensing, anthropological study of Indian oral traditions, and dendrochronology—which left Chacoan relics undisturbed—were pursued. In this vein, the "Chaco American Indian Consultation Committee" was established in 1991 to give Navajo, Hopi, Pueblo, and other Indian representatives a voice in park oversight. Current park policy mandates partial restoration of excavated sites. "Backfilling", or re-burying excavated sites with sand, is one such means. Other measures attempt to safeguard the area's ancient ambiance and mystique, such as the "Chaco Night Sky Program", which seeks to eliminate the effect of light pollution on the park's acclaimed night skies; under the program, some 14,000 visitors make use of the Chaco Observatory (inaugurated in 1998), park telescopes, and astronomy-related programs. The park was named a Gold-tier Dark Sky Park by the International Dark-Sky Association in 2013. Chacoan relics outside the current park's boundaries have been threatened by development: an