realities of their system." In the late 1950s, Rockford lost over 50,000 trees to Dutch elm disease, thinning the tree canopy of the "Forest City" for decades. From 1955 to 1965, several events would take place that would shape the development of Rockford into the 21st century. In 1956, construction was approved for a four-lane U.S 20 bypass; along with shifting truck traffic away from the downtown routing of the highway, the bypass established much of the southern border of the city (which remains to this day). In 1958, Interstate 90 was completed in Illinois, becoming the Northwest Tollway; in a decision that would change Rockford forever, the interstate highway was not routed through the city, but near the Winnebago-Boone county line, with the eastern terminus of the US 20 bypass in Cherry Valley. In 1963, the Rockford area was selected by Chrysler Corporation to construct an assembly plant; the final site of what is now the Belvidere Assembly Plant is southwest of Belvidere, between US 20 and Interstate 90. While not located directly in the city, the Chrysler assembly plant has served as one of the largest employers of the region since its 1965 opening. The growth of Rockford led to many changes to its educational systems. In 1955, Rockford College (now Rockford University) became co-educational for the first time. Coinciding with the expansion of the student body, the college outgrew its near-east side campus in use since the 1840s. Following the acquisition of land in 1957, construction began on its present-day campus location, opening in 1964. In 1964, Rock Valley College was founded as a two-year community college, with construction on its campus commencing in 1965. Prior to the 1960s, neighborhood and economic growth in Rockford largely mirrored itself on both sides of the Rock River. As the 20th century progressed, growth in western Rockford (and established neighborhoods in eastern areas of the city) struggled to compete with economic development that moved further east. From the late 1950s, downtown Rockford (centered around the intersection of IL 2 and US 20; Main Street and West State Street) began to decline as the primary shopping district of the city. In 1956, North Towne Mall opened on the far northwest side of the city, with Colonial Village opening on the (then) far east side in 1962, both of which were partially enclosed (some stores had exterior entrances). In 1973, Cherryvale Mall