Complex sentence: The concert was not broadcast in South Africa, so scale of the international event went largely unnoticed there.But created a big and strong ripple effect within the international community leading to the eventual release of Nelson Mandela from prison after 27 years of hard labor.
Split into simpler sentences: The concert was not broadcast in South Africa, so the scale of the international event went largely unnoticed there. But it created a big and strong ripple effect within the international community and later Nelson Mandela was released from prison after 27 years of hard labor.