The Art Institute of Chicago is a world-renowned art museum housing one of the largest permanent collections in the United States. An encyclopedic museum, the Art Institute collects, preserves, and displays works in every medium from all cultures and historical periods as well as hosts special exhibitions. With a collection of more than 260,000 artworks and artifacts, the museum has particularly strong holdings in Impressionist and Post-Impressionist painting, early twentieth-century European painting and sculpture, contemporary art, Japanese prints, and photography. In 2009, the museum completed the largest expansion in its 130-year history, the internationally acclaimed Modern Wing designed by Renzo Piano. Incorporating the latest in green museum technology, the 264,000- square-foot Modern Wing is dedicated to modern and contemporary art, photography, architecture and design, and new museum education facilities. In addition to displaying its permanent collection, the Art Institute mounts approximately forty special exhibitions per year and features daily lectures, gallery tours, and special performances.