Were built to commemorate the unification of South Africa under British rule. The two wings at the sides represent the Boerish (Afrikaans) and the English part of the population. The building's name comes from the time of the South African Union, which was only changed in 1961 to the current name, the Republic of South Africa.
More than 80 years later they were chosen as the place where South Africa's first democratically-elected president, Nelson Mandela, was inaugurated in May 1994.