Complex sentence: Club "Elegia"--the literary and art association which was established in Nakhodka in 1970, unites a wide range of poets, writers (including members of the Russian Union of writers), artists and musicians.
Split into simpler sentences: Club "Elegia"--the literary and art association which has arisen in Nakhodka in 1970. Unites a wide range of poets, writers (including members of the Russian Union of writers), and also artists and musicians.