The campus of Louisiana State University is located 1,000 acres south of downtown Baton Rouge. Most of the university's 250 buildings, most of which were built between 1925 and 1940, is located on a 650-acre plateau along the Mississippi River. The campus comprises libraries, art museums, some beautiful architecture, and it is full of greenery. The main library of Louisiana State University has nearly three million books and is located in the main quadrilateral library of the university. It is both a general library and a regional library of the United States, storing publications of the federal government, the United Nations, and the United States Patent and Trademark Office. There are several museums on the Louisiana State University campus, exhibiting students' original works and traveling exhibitions of local, national, and international artisans. In addition to the campus museum, the university currently operates four museums in the Greater Baton Rouge area: Art Museum, Natural History Museum, Natural Science Museum, and Rural Life Museum. There are currently more than 350 student organizations active in the institution, including a student government and a total of 36 fraternities and societies. This is the voice of the LSU student body in everything from university management to parking and transportation.