Johannesburg is the most populous city in South Africa, classified as a megacity; it is one of the 100 largest urban areas in the world. According to Demographia, the Johannesburg–Pretoria urban area is the 26th-largest in the world in terms of population, with 14,167,000 inhabitants. It is the provincial capital and largest city of Gauteng, which is the wealthiest province in South Africa. Johannesburg is the seat of the Constitutional Court, the highest court in South Africa. Most of the major South African companies and banks have their head offices in Johannesburg. The city is located within the mineral-rich Witwatersrand hills, the epicentre of the international-scale mineral, gold and diamond trade.
The city was established in 1886, following the discovery of gold, on what had been a farm. Due to the extremely large gold deposits found along the Witwatersrand, within ten years, the population had grown to over 100,000 inhabitants.
Wikipedia https://en.wikipedia.org/wiki/Johannesburg
Coordinates -26°12'18" N 28°2'58.999" E