Presented to the university by Paul Mellon (Yale College, Class of 1929), the Yale Center for British Art is a public art museum and research institute that houses the largest collection of British art outside of the United Kingdom. The collection reflects the development of British art and life from the Elizabethan period to the present day. In addition to the museum's physical collection, more than 70,000 images are freely available online. Academic resources include a Reference Library and Study Room for research and examining works up close. A world-renowned research institute and public art museum, the YCBA offers exhibitions and programs, including lectures, concerts, films, symposia, docent-led tours, and family events. The YCBA first opened to the public in April 1977 and is the final building designed by the internationally acclaimed architect Louis I. Kahn (1901–1974). The museum's four-story steel-and-glass exterior confers a monumental presence in downtown New Haven. Its interior is designed around two internal courtyards and is comprised of a restrained palette of natural materials including travertine, white oak, and Belgian linen. Kahn succeeded in creating intimate galleries where objects can be viewed in diffused natural light. His goal was to maximize daylight and use artificial illumination only on dark days or in the evening. The building’s design, materials, and sky-lit rooms provide an environment for the works of art that is simple and dignified. It is also the first museum in the United States to incorporate retail shops in its design, which includes the Museum Shop.