was the only route in the Parkways, Historic and Scenic Roads program to span multiple counties, and was the longest state-designated historic route in Arizona. Similar to US 66, US 80 was once a heavily traveled transcontinental U.S. Highway with an iconic car culture until Interstates bypassed and replaced it. Historic Route 66 is one of Arizona's four state designated Historic Routes, with the others being Historic US 80, the Jerome–Clarkdale–Cottonwood Historic Road (Historic US 89A) and the Apache Trail Historic Road. Major intersections This list follows the final non-freeway alignment in 1960. Structures Buildings A Desert Power & Water Co., Electric Power Plant built in 1908 closed in 1938, soon after the Hoover Dam was completed; it now houses a visitor information office, Route 66 Museum and gift shop. The Schoolhouse at Truxton Canyon Training School in Valentine operated from 1903 to 1937 as a mandatory boarding school in which Hualapai were separated from their families and put to work learning various trades. Long a symbol of forced assimilation, the historic building is now the property of the Hualapai Nation. The Peach Springs Trading Post, constructed in 1928 using local stone and logs, replaced an earlier 1917 trading post at Peach Springs. Its original role was to trade native crafts for foodstuffs, medicine and household goods. The building now houses Hualapai conservation offices. Lowell Observatory, an astronomical observatory established in Flagstaff in 1894, is one of the oldest observatories in the United States and a designated National Historic Landmark. The observatory is well known for being the location where astronomer Clyde Tombaugh discovered the dwarf planet Pluto on February 18, 1930. Flagstaff's Santa Fe Railway Depot, built in 1926, is currently an Amtrak station and includes a visitor information office. Flagstaff's 43-room Hotel Monte Vista was established in 1927 and is believed to be a filming location for the 1942 film Casablanca, starring actor Humphrey Bogart. Historic districts Kingman Commercial Historic District, Kingman Seligman Historic District, Seligman Railroad Addition Historic District, Flagstaff La Posada Historic District in Winslow, which dates from 1930, includes the Winslow Santa Fe station as well as La Posada Hotel and Gardens, a Fred Harvey Company hotel. Restaurants Delgadillo's Snow Cap Drive-In in Seligman, was built in 1953 with scrap railway lumber by Juan Delgadillo. Following Delgadillo's passing in 2004, his children took over ownership and operation of the restaurant. It continues to offer choices