The city of Tucson is 2,389 feet above sea level and covers nearly 500 square miles. The landscape is varied and includes flowering desert, rolling hills, winding dry riverbeds, rugged canyons and pine-topped peaks, all beneath a clear, blue sky. Scenery on the 90-minute drive from downtown Tucson to the top of the highest mountain peak in the Santa Catalina Mountains, Mt. Lemmon, is like what you'd see on a trip from Mexico to Canada. Sentinel Peak (also called "A" Mountain) is on the western fringe of the downtown historic district. The base of this peak is the site of a major archaeological dig for remnants of Tucson's earliest settlement, about 4,000 years ago. Tucson's Great Outdoors