events, and complements Petrillo Music Shell, the park's older and larger bandshell. The pavilion is built partially atop the Harris Theater for Music and Dance, the park's indoor performing arts venue, with which it shares a loading dock and backstage facilities. The pavilion is seen as a major upgrade from the Petrillo Music Shell for those events it hosts. Initially, the pavilion's lawn seats were free for all concerts, but this changed when Tori Amos performed the first rock concert there on August 31, 2005. The Pritzker Pavilion is the home of the Grant Park Symphony Orchestra and Chorus and the Grant Park Music Festival, the nation's only remaining free, municipally supported, outdoor, classical music series. The Festival is presented by the Chicago Park District and the Chicago Department of Cultural Affairs. The Pavilion hosts a wide range of other music series and annual performing arts events. Performers ranging from mainstream rock bands to classical musicians and opera singers have appeared at the pavilion, which also hosts physical fitness activities such as yoga. All rehearsals at the pavilion are open to the public; trained guides are available for the music festival rehearsals, which are well-attended. The construction of the pavilion created a legal controversy, given that there are historic limitations on the height of buildings in Grant Park. To avoid these legal restrictions, the city classifies the bandshell as a work of art rather than a building. With several design and assembly problems, the construction plans were revised over time, with features eliminated and others added as successful fundraising allowed the budget to grow. In the end, the performance venue was designed with a large fixed seating area, a Great Lawn, a trellis network to support the sound system, and a headdress fashioned from signature Gehry stainless steel. It features a sound system with an acoustic design that replicates an indoor concert hall sound experience. The pavilion and Millennium Park have received favorable recognition by critics, especially for their accessibility; an accessibility award ceremony held at the pavilion in 2005 described it as "one of the most accessible parks—not just in the United States but possibly the world". Grainger Plaza and Cloud Gate The Grainger Plaza (formerly AT&T Plaza) is a public space that hosts the Cloud Gate sculpture. The plaza opened in July 2004 with the unveiling of the sculpture during the grand opening weekend of the park. Ameritech