Question: 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?
Sentence (from "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.
Relevant evidence: Yes