Complex sentence: Paul McCartney's performance there was a historic moment for many, as The Beatles were banned in the Soviet Union, preventing any live performances there of any of The Beatles; the Soviet Union also banned the sales of Beatles records.
Split into simpler sentences: Paul McCartney's performance there was a historic moment for many, as The Beatles were banned in the Soviet Union, preventing any live performances there of any of The Beatles. The Soviet Union also banned the sales of Beatles records.