Robben Island was a prison for political prisoners and criminals during the Apartheid years in South Africa. The prison was a harsh one, designed to silence anyone who spoke out against the laws. However, many of the prisoners, despite the harsh conditions, were able to rise above these hardships.
Today, to visit, you will take a 45 minute boat ride from Cape Town to Robben Island. Once there, you will receive a bus tour and then a guided tour by one of the actual prisoners.
It is definitely a place worth stopping by when in Cape Town.