Embassy during the Cold War, the Soviet Embassy said "their voices are a treasure of art" and viewed them highly in bettering understanding between the Soviet Union and the United States. Guest conductors Dennis Russell Davies and Charles Dutoit have conducted the Choir for performances of Mendelssohn's Midsummer Night's Dream and the concert version of Puccini's La Bohème with the Philadelphia Orchestra. During the 1990s, the Choir added Benjamin Britten's War Requiem to its repertoire under the baton of Wolfgang Sawallisch, as well as the concert version of Carl Orff's Carmina Burana, conducted by Zdenek Macal in 1996 with the Choral Arts Society. They sang in 1992 at the Sydney Opera House to a sold out audience. Each year, the Pennsylvania Ballet hosts the Choir as part of their seasonal favorite, The Nutcracker. Internationally, the Choir singers have performed for the Royal Families of Sweden, Denmark, England, Thailand and in over 30 countries around the world. In 2008, the choir celebrated its anniversary with a concert at the Irvine Auditorium and a tour to Spain, a first for the choir. In 2009, the choir went to South America after a successful performance at Carnegie Hall in New York City. Over the years, the choir has become a household name in the Philadelphia area. They have also sung at the White House for four presidents. More recently, the choir sang for then-candidate Barack Obama in Germantown and Laura Bush at the Cityline Hotel in Philadelphia. Major annual concerts Philadelphia Boys Choir and Chorale performs two major annual concerts: the Winter and Spring concerts. The Winter concert consists of mostly Christmas music, pop songs, and traditional carols. The concert is often performed in churches, theaters, and the occasional concert hall. The concert is performed with a select orchestra and is a family favorite for the entire Delaware Valley. The spring concert has, for the past few years, been at the Kimmel Center in Philadelphia, and is often themed, so stage settings, choir fundraisers, and the music selections follow a central motif. The musical styles have ranged from full classical choral or orchestral works (such as Orff's Carmina Burana) to pop and other modern choral compositions. The Spring concert offers the most diversity of repertoire, and is often considered the more musically sophisticated of the two. Concert venues have included the Kimmel Center in Philadelphia, Philadelphia's Academy of Music, Irvine Auditorium, and numerous