Tamberg's Concerto Grosso, Op. 5 was awarded a gold medal at the 6th World Festival of Youth and Students, which was held in what city?
Concerto Grosso (Tamberg): Eino Tamberg's Concerto Grosso, Op. 5, was composed in 1956. Concerto Grosso (Tamberg):  It was awarded a gold medal at the 6th World Festival of Youth and Students the following year and was subsequently performed through both the Eastern and Western Blocs, launching the Estonian composer's career. 6th World Festival of Youth and Students: The 6th World Festival of Youth and Students (Russian: Всемирный фестиваль молодёжи и студентов) was opened on 28 July 1957, in Moscow, Soviet Union.
Moscow, Soviet Union