Thirty years ago, the anti-apartheid champion Nelson Mandela was released after spending 27 years behind bars. The man who, four years later, would become South Africa's first black president was the most famous inmate of Robben Island, now the country's most visited museum. With its 350,000 tourists every year, the former prison is an important symbol for the Rainbow Nation, where dialogue and reconciliation are a reality. But the museum has nevertheless faced strike action. Our correspondents report.