UC system in 1958, many new buildings and additions were laid out over the following decade. Following an east-west axis, new student residence halls and athletic facilities were developed along the southeastern quadrant of the main campus, while academic and research facilities were built up along the central campus area closer to the freeway. The Carillon Tower, the only ornamental structure on campus, was built in this period. Past the freeway, over of agricultural fields extended northwest to the intersection of Chicago Avenue and Le Conte Drive, forming the borders of "West Campus." After the drop in enrollment and subsequent restructuring of academic programs in the 1970s, little capacity construction was undertaken over the next two decades, except as required by the developing research interests of CNAS. Boyce Hall, completed in 1974, was the only major addition in the period, although several greenhouses and agricultural support units continued to be built. However, in the mid-80s, enrollment started to grow significantly, by 76% over six years (from 4,655 students in 1983 to 8,220 students in 1989). This growth justified considerable further campus expansion over the 1990s. Major additions built in the 90s include the Entomology Research Museum completed in 1993, Bourns Hall completed in 1995, the Humanities & Social Science building in 1996, the Science Library in 1998, Pentland and Stonehaven residence halls in 2000, and the Arts building in 2001. Since 1999, to accommodate a further wave of enrollment growth, more than $730 million have been invested in new construction projects. Active construction projects include: Phase II of the Campus Commons expansion, Engineering Unit 3 and Materials Science Building, Psychology Research Building, Genomics Building, CHASS Instructional and Research Center, and a new Students Academic Support Services Building. The Campus Commons (Phase I), 'Glen Mor' Arroyo Student Housing Apartments, and Alumni & Visitors Center were recently completed. East campus notable features East Campus, comprising approximately , provides the core cluster of academic buildings and services. Student housing and recreational facilities are provided in its northern and easternmost portion near the Box Spring Mountains. Wide grassy pedestrian malls run throughout the campus. In the center of the main campus stands the UCR Carillon Bell Tower, one of only four in California. It was given as a gift by former UC regent Philip L. Boyd and his wife Dorothy. The dedication of the carillon and tower took place on October 2, 1966. Designed