What is the name of the Finnish rock festival held on an island in Turku, which is one of the oldest in Europe?

Explanation

Ruisrock is an annual rock festival in Finland. The festival has taken place on the island of Ruissalo in Turku since 1970, and is the second oldest rock festival in Europe. Around 70 000 music lovers from across the world visit Ruisrock. This is somewhat lower than the record 100 000 visitors received in 1971. The program predominantly features rock music bands.