London’s Royal Festival Hall is closed for extensive renovations. “The closing of the roughly 3,000-seat Festival Hall — a regular stopping point on the Famous Performer circuit (from Callas to Hendrix to Karajan) — was traumatic, said Michael Lynch, the chief executive of the South Bank Center. The center comprises Royal Festival Hall, the smaller Queen Elizabeth Hall, the even smaller Purcell Room, the Jubilee Gardens and the Hayward Gallery. The renovation, more than 20 years in the making, is part of a revitalization of the complex.”