Mention two public holidays on the south African calendar that promote nation-building .
1. Human Rights Day (21 March) - This holiday commemorates the Sharpeville massacre of 1960 and promotes unity and equality among all South Africans regardless of race, religion, or background.
2. Heritage Day (24 September) - This holiday celebrates South Africa's diverse cultural heritage and encourages people to embrace and appreciate the country's different traditions and customs. It promotes unity and understanding among the various ethnic groups in the country.