Founded in 1848, by an act of the Great and General Court of Massachusetts, the Boston Public Library (BPL) was the first large free municipal library in the United States. The Boston Public Library's first building of its own was a former schoolhouse located on Mason Street that was opened to the public on March 20, 1854. The library's collections approximated 16,000 volumes, and it was obvious from the day the doors were first opened that the quarters were inadequate. In the latter half of the 19th century, the library worked vigorously to develop and expand its branch system. Viewed as a means to extend the library's presence throughout the city, the branch system evolved from an idea in 1867 to a reality in 1870, when the first branch library in the United States was opened in East Boston. Between 1872 and 1900, 21 more branches began serving communities throughout Boston's diverse neighborhoods. Over 3 million people visit the BPL each year, many in pursuit of research material, others looking for an afternoon's reading or the use of the computer or to attend a class, still others for the magnificent and unique art and architecture of many library locations. There were over 7 million visits to the library's website last year and more than 3.5 million books and audiovisual items borrowed or downloaded.