From Wikipedia: http://en.wikipedia.org/wiki/Union_Buildings

The Union Buildings (Afrikaans: Die Uniegebou) form the official seat of the South African government and also house the offices of the president of South Africa. The imposing buildings are located in Pretoria, atop Meintjieskop at the northern end of Arcadia, close to historic Church Square and the Voortrekker Monument. The large gardens of the Buildings are nestled between Government Avenue, Vermeulen Street East, Church Street, the R104 and Blackwood Street. Fairview Avenue is a closed road where only officials can enter to the Union Buildings. Though not in the center of Pretoria the Union Buildings occupy the highest point of Pretoria, and constitute a South African national heritage site.