Two Nordic anniversaries launch this year鈥檚 成人快手 Proms: Denmark鈥檚 Carl Nielsen and Finland鈥檚 Jean Sibelius both celebrate their 150th-birthday years. Two exotic musical retellings of the story of the Babylonian king Belshazzar include the first of this summer鈥檚 feast of choral works. Celebrated German pianist Lars Vogt is soloist in the first of six late great Mozart piano concertos, and British composer Gary Carpenter spearheads the 32 premieres this season 鈥� a musical taste of things to come.