On November 9, 2010, Metallica announced it would be headlining the Rock in Rio festival in Rio de Janeiro on September 25, 2011. On December 13, 2010, the band announced it would again play as part of the "big four" during the Sonisphere Festival at Knebworth House, Hertfordshire, on July 8, 2011. It was the first time all of the "big four" members played on the same stage in the UK. On December 17, 2010, Another "big four" Sonisphere performance that would take place in France on July 9 was announced. On January 25, 2011, another "big four" performance on April 23, 2011, at the Empire Polo Club in Indio, California, was announced. It was the first time all of the "big four" members played on the same stage in the U.S. On February 17, 2011, a show in Gelsenkirchen, Germany, on July 2, 2011, was announced. On February 22, a "big four" show in Milan on July 6, 2011, was announced. On March 2, 2011, another "big four" concert, which took place in Gothenburg on July 3, 2011, was announced. The final "big four" concert was in New York City, at Yankee Stadium, on September 14, 2011.