Canyons of the Ancients National Monument encompasses 164,000 acres of southwest Colorado and was established on June 9, 2000, to protect the cultural and natural resources of its canyons and mesas. For hundreds of years, the canyons and mesas in what is now the Four Corners were inhabited by the Ancestral Puebloans. Archaeologists estimate that tens of thousands of sites lie within the monument, giving it the highest density of archeological sites in the nation, with some areas containing more than 100 sites per square mile and some village sites covering 10 acres or more. The monument is administered by the Bureau of Land Management. Lowry Pueblo, on County Road CC about 12 miles west of Pleasant View, is a 1,000-year-old Ancestral Puebloan village constructed around AD 1060 and inhabited for about 165 years; it began as a small village with a single kiva and grew to 40 rooms, eight kivas, and a Great Kiva before it was abandoned. The Anasazi Heritage Center, on Highway 84 about 3 miles west of Dolores, offers exhibits, galleries, and interactive programs on Ancestral Puebloan resources found throughout the Four Corners. Along the southern edge of the monument, McElmo Canyon on County Road G follows a historic route and provides access to hiking trails in side canyons including Sand and Rock Creek canyons, where Ancestral Puebloan sites stand in natural sandstone alcoves.