Opera house as they sing. This occurs in the Met's productions of operas such as "Aida" and "Tales of Hoffman". London's Royal Opera House, which was remodeled in the late 1990s, retained the original 1858 auditorium at its core, but added completely new backstage and wing spaces as well as an additional performance space and public areas. Much the same happened in the remodeling of Milan's La Scala opera house between 2002 and 2004. Although stage, lighting and other production aspects of opera houses often make use of the latest technology, traditional opera houses have not used sound reinforcement systems with microphones
Metropolitan Opera House (Lincoln Center) premieres of operas, including John Corigliano's "The Ghosts of Versailles", Phillip Glass's "The Voyage" and the US premiere of Nico Muhly's "Two Boys" in 2013. When the Metropolitan Opera is on hiatus, the Opera House is home to the annual Spring season of American Ballet Theatre (ABT). It regularly hosts touring opera and ballet companies including the Kirov, Bolshoi, and the La Scala companies. In addition, the Met has presented recitals by Vladimir Horowitz, Renée Fleming, Kathleen Battle and others. Philip Glass's "Einstein on the Beach" was staged independently at the Met in 1976. Concerts by Barbra Streisand, The Who,