River (the former site of the Philadelphia Civic Center and a nearby site owned by the United States Postal Service). Dubbed the Postal Lands, the site extends from Market Street on the north to Penn's Bower Field on the south, including the former main regional U.S. Postal Building at 30th and Market Streets, now the regional office for the U.S. Internal Revenue Service. Over the next decade, the site became the home to educational, research, biomedical, and mixed-use facilities. The first phase, comprising a park and athletic facilities, opened in the fall of 2011. In September 2011, Penn completed the construction of the $46.5 million, Penn Park, which features passive and active recreation and athletic components framed and subdivided by canopy trees, lawns, and meadows. It is located east of the Highline Green and stretches from Walnut Street to South Streets. Penn maintains two arboreta. The roughly The Penn Campus Arboretum at the University of Pennsylvania encompasses the entire University City campus. The campus arboretum is an urban forest with over 6,500 trees representing 240 species of trees and shrubs, ten specialty gardens and five urban parks, which has been designated as a Tree Campus USA since 2009 and formally recognized as an accredited ArbNet Arboretum since 2017. Penn maintains an interactive website linked to Penn's comprehensive tree inventory, which allows users to explore Penn's entire collection of trees. Penn also owns and operates the Morris Arboretum in Chestnut Hill in northwestern Philadelphia. The Morris Arboretum is also the official arboretum of the Commonwealth of Pennsylvania. New Bolton Center veterinary campus Penn also owns the New Bolton Center, the research and large-animal health care center of its veterinary school. Located near Kennett Square, New Bolton Center received nationwide media attention when Kentucky Derby winner Barbaro underwent surgery at its Widener Hospital for injuries suffered while running in the Preakness Stakes. Libraries Penn's library began in 1750 with a donation of books from cartographer Lewis Evans. Twelve years later, then-provost William Smith sailed to England to raise additional funds to increase the collection size. Benjamin Franklin was one of the libraries' earliest donors and, as a trustee, saw to it that funds were allocated for the purchase of texts from London, many of which are still part of the collection, more than 250 years later. Penn library system has grown into a system of 14 libraries with 400 full-time equivalent (FTE)